identifier: Ahmadi, Roozbeh  (2012) Optical Microsystems for Static and Dynamic Tactile Sensing: Design, Modeling, Fabrication and Testing.  PhD thesis, Concordia University.

abstract:
Minimally invasive surgical operations encompass various surgical tasks ranging from conventional endoscopic/laparoscopic methods to recent sophisticated minimally invasive surgical techniques. In such sophisticated techniques, surgeons use equipment varying from robotic-assisted surgical platforms for abdominal surgery to computer-controlled catheters for catheter-based cardiovascular surgery. Presently, the countless advantages that minimally invasive surgery offers for both patients and surgeons have made the use of such surgical operations routine and reliable. However, in such operations, unlike conventional surgical operations, surgeons still suffer from the lack of tactile perception while interacting with the biological tissues using surgical instruments. To address this issue, it is necessary to develop a tactile sensor that can mimic the fingertip tactile perceptions of surgeons. In doing so and to satisfy the needs of surgeons, a number of considerations should be implemented in the design of the tactile sensors.
First, the sensor should be magnetic resonance compatible to perform measurements even in the presence of magnetic resonance imaging (MRI) devices. Currently, such devices are in wide-spread use in surgical operation rooms. Second, the sensor should be electrically-passive because introducing electrical current into the patients’ body is not desirable in various surgical operations such as cardiovascular operations. Third, the sensor should perform measurements under both static and dynamic loading conditions during the sensor-tissue interactions. Such a capability of the sensor ensures that surgeons receive tactile feedback even when there is continuous static contact between surgical tools and tissues. Essentially, surgeons need such feedback to make surgical tasks safer. In addition, the size of the sensor should be miniaturized to address the size restrictions. In fact, the combination of intensity-based optical fiber sensing principles and micro-systems technology is one of the limited choices that address all the required considerations to develop such tactile sensors in a variety of ways.
The present thesis deals with the design, modeling, manufacturing, testing, and characterizing of different tactile sensor configurations based on detection and integration methods. The various stages of design progress and principles are developed into different design configurations and presented in different chapters. The main sensing principle applied is based on the intensity modulation principle of optical fibers using micro-systems technology. In addition, a hybrid sensing principle is also studied by integrating both optical and non-optical detection methods. The micromachined sensors are categorized into five different generations. Each generation has advantages by comparison with its counterpart from the previous generation. The initial development of micromachined sensors is based on optical fiber coupling loss. In the second phase, a hybrid optical-piezoresistive sensing principle is studied. The success of these phases was instrumental in realizing a micromachined sensor that has the advantage of being fully optical. This sensor measures the magnitude of concentrated and distributed force, the position of a concentrated force, the variations in the force distribution along its length, the relative hardness of soft contact objects, and the local discontinuities in the hardness of the contact objects along the length of the contact area. Unlike most electrical-based commercially-available sensors, it performs all of these measurements under both static and dynamic loading conditions. Moreover, it is electrically passive and potentially MRI-compatible. The performances of the sensors were experimentally characterized for specific conditions presented in this thesis. However, these performances are easily tunable and adjustable depending upon the requirements of specific surgical tasks. Although the sensors were initially designed for surgical applications, they can have numerous other applications in the areas of robotics, automation, tele-display, and material testing.


identifier: Safaei Takhtehfouladi, Elham  (2012) Inactivation of Clostridium perfringens Spores in Anaerobically Digested Biosolids During BioElectroTM Disinfection Process.  PhD thesis, Concordia University.

type: Thesis NonPeerReviewed

abstract:
Treatment of municipal liquid wastes generates immense quantities of sludges that demands environmentally safe disposal or reuse. The past 40 years have seen the emergence of an increasing desire worldwide to attenuate the disposal of biosolids to landfills and to promote the options of the agricultural application of this by-product as soil conditioner and fertilizer. Consequently, post-treatment steps are commonly required as a means to adapt biosolids to the requirements of environmental legislations. Conventional methods are not generally effective enough; hence, novel and emerging methods are continually being sought.
This study was initiated to develop an eco-efficient process that produces a pathogen-free biosolids product which can be used beneficially for land application
to meet or better stringent public health and environmental concerns. To achieve this goal BioElectroTM, an enhanced 2D electric field process, was developed. The biosolids treatment experiments were performed at the average initial temperature, pH and ORP of 18°C, 8.17 and -57.3 mV, respectively. Clostridium perfringens spores in anaerobically digested biosolids were used as the bioindicator to assess the eficiency of BioElectroTM process. It was evident that electrical field intensity
between 2.5-2.8 (V/cm) was capable of reducing the number of viable C. perfringens spores below ceiling levels (>3 LRs).
Furthermore, the mechanism of disinfection during BioElectroTM process was evaluated. Statistically significant effects of electric field intensity (E) and applied enhancement agents were ascertained at each time interval using multiple linear regression (MLR). Moreover, the shape of inactivation curves resulting from the
BioElectroTM treatment showed a triphasic pattern, starting with a short linear part at low treatment times, followed by a shoulder or a lag period and finally a first-order inactivation kinetics. This was explained by effects of multiple stressors and mechanism of disinfection during the BioElectroTM treatment. Ultrastructural analyses using transmission electron microscope were performed
to investigate physiological changes in the fitness of treated spores. It was observed that electric field can be considered as an inducing factor in activating and con-
sequent germination of dormant spore, and that can be responsible for shoulder formation in survival curves.
Also, an empirical model was developed by non-linear programming approach to quantify disinfection kinetics of BioElectroTM disinfection process. The proposed
model was able to predict the spore inactivation very accurately.


identifier: Sooch, Gurinderbir Singh  (2011) Methodologies for Seismic Assessment of Concrete Gravity Dam-Foundation Systems.  Masters thesis, Concordia University.

abstract:
The number and size of hydroelectric dams have increased greatly across the Canadian landscape since 1910. The concrete gravity dams should perform satisfactorily during a seismic event as in case of failure, the release of impounded reservoir water can cause catastrophic damage in the downstream communities.  Traditionally the foundation in a dam is modeled by a sub-structuring approach for the purpose of seismic performance analysis. The main disadvantage of sub-structuring approach is that it cannot be used for solving nonlinear dynamic problems. Therefore, in that case seismic response analysis must be carried out in time domain as it allows inclusion of nonlinear behavior in a system. In this study, different earthquake input mechanisms has been studied considering the following models A) massless foundation , B) free-field earthquake input at dam foundation interface and  C) deconvolved earthquake input model. Deconvolution is a mathematical process which allows the adjustment of the amplitude and frequency contents of an earthquake ground motion applied at the base of the foundation to achieve the desired output at the dam-foundation interface. It has been observed that the existing procedures of deconvolution are inadequate for the high frequency earthquake records. A Modified deconvolution procedure has been proposed here for efficient deconvolution of high frequency earthquake records.The above discussed input mechanisms are studied in more detail with two different geometrical models. It has been found that model C is the most rational and accurate one compared to the other models.

In the second part of this study elastic and inelastic analysis of dams with different geometries has been performed to study the existing guidelines for the seismic assessment of dams. The performance of the dam models has been assessed using both the high frequency and low frequency earthquake records scaled at 0.35g. Based on the study it can be concluded that the different numerical models induce slight differences in the results relating to the tensile damage in dam foundation system. However, the results are consistent with each other. Also, the results from the linear elastic analysis provided valuable insight about seismic performance of concrete gravity dams but they fail to account for the existing deterioration in the dam.


identifier: Roosta Pour, Laleh  (2012) A hybrid ABox calculus using algebraic reasoning for the Description Logic SHIQ.  Masters thesis, Concordia University.

abstract:
We present a hybrid tableau calculus for the description logic (DL) SHIQ. The presented algorithm decides SHIQ ABox consistency and uses an algebraic approach for more informed
reasoning about qualified number restrictions (QNRs). Benefiting from integer linear programming and several  optimization techniques to deal with the interaction of QNRs and inverse roles, our approach provides a more deterministic and informed calculus. In addition, a prototype reasoner based on the hybrid calculus has been implemented that decides concept satisfiability for ALCHIQ. We provide a set of benchmarks that demonstrate the effectiveness of our hybrid reasoner in comparison to other DL reasoners.


identifier: You, Jianliang  (2012) Compliant Torsional Micromirrors with Electrostatic Actuation.  PhD thesis, Concordia University.

abstract:
Due to the existence of fabrication tolerance, property drift and structural stiction in MEMS (Micro Electro Mechanical Systems), characterization of their performances through modeling, simulation and testing is essential in research and development. Due to the microscale dimensions, MEMS are more susceptible and sensitive to even minor external or internal variations. Moreover, due to the current limited capability in micro-assembly, most MEMS devices are fabricated as a single integrated micro-mechanical structure composed of two essential parts, namely, mass and spring, even if it may consist of more than one relatively movable part. And in such a scale of dimensions, low resonant micro-structures or compliant MEMS structures are hard to achieve and difficult to survive. Another problem arises from the limited visibility and accessibility necessary for characterization. Both of these issues are thus attempted in this research work.

An investigation on micromirrors with various actuations and suspensions is carried out, with more attention on the micromirrors with compliant suspensions, electrostatic actuation and capable of torsional out-of-plane motion due to their distinct advantages such as the low resonance and the low drive voltage. This investigation presents many feasible modeling methods for prediction and analysis, aiming to avoid the costly microfabrication. Furthermore, both linear and nonlinear methods for structure and electrostatics are all included. Thus, static and dynamic performances of the proposed models are formularized and compared with those from FEA (Finite Element Analysis) simulation. The nonlinear modeling methods included in the thesis are Pseudo Rigid Body Model (PRBM) and hybrid PRBM methods for complex framed microstructures consisting of compliant beam members.

The micromachining technologies available for the desired micromirrors are reviewed and an SOI wafer based micromachining process is selected for their fabrication. Though the fabrication was executed outside of the institution at that time, the layout designs of the micro-chips for manufacture have included all related rules or factors, and the results have also demonstrated the successful fabrication.

Then investigation on non-contact test methods is presented. Laser Doppler Vibrometer (LDV) is utilized for the measurement of dynamic performances of proposed micromirrors. Two kinds of photo-sensing devices (PSDs), namely, the digitized PSD formed by CCD arrays and the analog PSD composed of a monolithic photosensing cell, are used for static test set-ups. An interferometric method using Mirau objective along with microscope is also employed to perform static tests of the selected micromirrors. Comparison of the tested results and their related theoretical results are presented and discussed, leading to a conclusion that the proposed hybrid PRBM model are appropriate for prediction or analysis of compliantly suspended micromirrors including issues arising from fabrication tolerance, structural or other parametric variations.


identifier: Uddin, Mohammad Faisal  (2012) Design methods for optimal resource allocation in wireless networks.  PhD thesis, Concordia University.

abstract:
Wireless communications have seen remarkable progress over the past two decades and perceived tremendous success due to their agile nature and capability to provide fast and ubiquitous internet access. Maturation of 3G wireless network services, development of smart-phones and other broadband mobile computing devices however have motivated researchers to design wireless networks with increased capacity and coverage, therefore un-leaching the wireless broadband capabilities. In this thesis, we address two very important design aspects of wireless networks, namely, interference management and control through optimal cross-layer design and channel fading mitigation through relay-assisted cooperative communications. For the former, we address, in the context of wireless network design, the problem of optimally partitioning the spectrum into a set of non-overlapping channels with non uniform spectrum
widths and we model the combinatorially complex problem of joint routing, link scheduling, and spectrum allocation as an optimization problem. We use column generation decomposition technique (which decomposes the original problem into a master and a pricing subproblem) for solving the problem optimally. We also propose several sub-optimal methods for efficiently solving the pricing subproblems. For the latter problem, we study the joint problem of relay selection and power allocation in both wireless unicast and multicast cooperative cellular networks. We employ convex
optimization technique to model this complex optimization problem and use branch and bound technique to solve it optimally. We also present sub-optimal methods to reduce the problem complexity and solve it more efficiently.


identifier: Smadi, Othman Ahmed  (2011) Numerical and Experimental Investigations of Pulsatile Blood Flow through a Dysfunctional Mechanical Heart Valve.  PhD thesis, Concordia University.

abstract:
Despite the marked improvement in prosthetic heart valve design and functionality, thromboembolism, structural failure, endocarditis and hemolysis are still possible complications. In such cases, native heart valve disease is replaced with “prosthetic heart valve disease”. Bileaflet Mechanical Heart Valve (BMHV) dysfunction can cause serious and potentially fatal complications.
In vivo, in vitro, and Computational Fluid Dynamics (CFD) studies were conducted on dysfunctional BMHVs in order to: (1) investigate the relationship between blood flow patterns downstream of the dysfunctional BMHV and the levels of hemolysis and/or thrombus formation; (2) to evaluate the limitations of the hemodynamic parameters and cutoff values suggested by the American Society of Echocardiography (ASE) guidelines; and (3) to improve the accuracy of the current diagnosis methods using the same clinical modalities and settings.
Pulsatile two-dimensional and two phase flow numerical simulations revealed that the flow upstream and downstream of a dysfunctional mechanical heart valve was highly influenced by dysfunction severity and this resulted in discrepancies between Doppler echocardiography and numerically derived transvalvular pressure gradients. Moreover, the flow downstream of the dysfunctional valve was characterized by abnormally elevated shear stress and large-scale vortices. These flow characteristics can predispose to blood components damage.
Three-dimensional Fluid-Structure Interaction (FSI) numerical modeling showed that the flow nature is three-dimensional and time dependent, especially with the existence of valve dysfunction. A pulsatile 3-D FSI numerical model should be used when the evolution of the vortical structure downstream of the BMHV is the objective of the study. Only flow characteristics through the central orifice are measured by the current diagnosis methods. Therefore, revisiting the assumptions and the theory behind the current clinical method is critical in order to include the flow through the two lateral orifices.
A practical mathematical model was proposed for predicting the normal reference values of Doppler-derived parameters for BMHVs. The new theoretical model overcomes the shortcomings of the parameters suggested by the ASE guidelines by taking into account flow conditions (Left Ventricle Outflow Tract (LVOT) measurements), valve size and valve type.  The accuracy of diagnosis significantly improved using the new theoretical parameters compared to those suggested by the ASE. Finally, the new method improved the way to evaluate of the performance of BMHVs, not only after implantation, but also early during the stage of design and manufacturing.


identifier: Placide, Virginie  (2011) Nouveaux glycoclusters à coeur pyrène: Synthèse et interactions envers des lectines.  PhD thesis, Concordia University.

abstract:
Résumé :
Nouveaux glycoclusters fluorescents à cœur pyrène : Synthèse et interactions envers des lectines
Virginie Placide, Ph.D.
Concordia University, 2011
Les interactions sucre-protéine sont à la base de nombreux phénomènes biologiques tels que l’adhésion de bactéries sur les surfaces de cellules hôtes. L’inhibition de ce type d’interaction par des molécules multivalentes synthétiques (comme les glycopolymères, glycodendrimères, glycoclusters, etc.) fait l’objet d’études importantes depuis plusieurs décennies. L’obtention de telles molécules pourrait permettre de développer de nouvelles thérapies qui pourraient palier notamment à la résistance aux antibiotiques. De plus, la détection de telles interactions par des méthodes simples et faciles à mettre en œuvre permettrait une amélioration de la compréhension de ces phénomènes. C’est dans ce contexte, que nous avons développé une nouvelle classe de composés glycosylés multivalents fluorescents. Ces glycoclusters, ont la particularité de présenter une double fonctionnalité : l’inhibition d’interactions lectine-sucre par des effets de multivalence ; ainsi qu’une détection de ces interactions grâce à la spectroscopie de fluorescence.
Nous présentons dans ce manuscrit, la synthèse d’une nouvelle famille de glycoclusters mannosylés à cœur pyrène fluorescent. De plus, les résultats des analyses biologiques (ITC, SPR, HIA) et physicochimiques (DLS, spectroscopie de fluorescence) réalisées sur des lectines d’intérêt (ConA, LecB, Bc2lA) en présence des glycoclusters sont discutés. Nous avons ainsi mis en évidence la possibilité de reconnaître et de détecter les interactions lectine-sucre par la spectroscopie de fluorescence.

Abstract :
New Fluorescent Glycoclusters with Pyrene core : Synthesis and Interactions with Lectins
Virginie Placide, Ph.D.
Concordia University, 2011
Carbohydrate-proteins interactions are of main importance because they are involved in many biological phenomena such as bacterial adhesion on host cells. A growing interest was recently shown concerning the development of synthetic multivalent macromolecules (glycopolymers, glycodendrimers, glycoclusters, etc) for the inhibition of such interactions. Indeed, it could protect some host cells from bacteria aggression. Moreover, the detection of thoses interactions would allow a better understanding of such phenomena. The purpose of this work is to design some new fluorescent glycoclusters which exhibit dual functionality: the inhibition of carbohydrate-protein interactions via a multivalency effect; and detection of the interactions via fluorescence spectroscopy.
A new class of biosensors was created based on the synthesis of a new family of fluorescents glycoclusters (divalent and tetravalent) containing fluorescent pyrene core. Moreover, some biological (ITC, SPR, HIA) and biophysical analyses (DLS, fluorescence) involving some lectins (ConA, LecB, Bc2lA), will be presented and discussed. We have shown the possibility for detecting some carbohydrate-protein interactions, using fluorescence spectroscopy.


identifier: Amir, Ella  (2012) The Experience of Family Members in the Context of Mental Illness: Caregiving Burden, Personality Constructs and Subjective Well-Being.  PhD thesis, Concordia University.

abstract:
This longitudinal study examined psychological factors that can contribute to subjective well-being among 147 individuals who are the primary caregivers of family members with mental illness. It was hypothesized that adaptive personality constructs and the personality profiles they create would predict higher levels of subjective well-being by facilitating coping with caregiving stress. In addition, it was investigated whether caregiving burden would mediate the associations between personality constructs, coping, and well-being, or whether personality would moderate the associations between burden, coping, and well-being.
The personality constructs included goal adjustment capacities (goal disengagement and goal reengagement, Wrosch, Scheier, Miller, Schulz, & Carver, 2003), dispositional optimism (Scheier & Carver, 1987), and unmitigated communion (Helgeson & Fritz, 1998). Indicators of well-being included positive and negative affect, life satisfaction, depressive symptoms, and purpose in life.
The cross-sectional and longitudinal results indicated that goal disengagement, goal reengagement, and optimism predicted higher levels of several indicators of subjective well-being. Unmitigated communion was associated only with negative affect and depressive symptoms. Caregiver burden was negatively associated with goal disengagement and optimism, but positively with goal reengagement, and explained some of the effects of these personality constructs. Moreover, goal adjustment capacities predicted improved well-being among highly burden participants, while optimism was associated with higher well-being among their less burdened counterparts. In addition, some personality profiles, created by interactions between the three personality
constructs, were meaningfully associated with subjective well-being. Finally, certain coping behaviors were associated with goal adjustment capacities and optimism but not with unmitigated communion. Effective and less useful care-specific coping mediated the effects of goal adjustment capacities and optimism on participants’ subjective well-being.
Overall, the study’s findings suggest that different personality constructs can influence the subjective well-being of individuals caring for mentally ill family members. Moreover, many of these effects could be statistically explained by the way individuals cope with caregiving stress. These findings have important implications for theories of personality functioning and adjustment to stressful life circumstances. In addition, they illuminate pathways to subjective well-being, which has important practical implications for helping caregivers manage their difficult life circumstances and improve their quality of life.


identifier: Hasan, Shadi  (2012) Design and Performance of a Pilot Submerged Membrane Electro-Bioreactor (SMEBR) for Wastewater Treatment.  PhD thesis, Concordia University.

abstract: The quality of wastewater treatment plants effluents in Canada, and more specifically in Quebec is of a huge concern. Hence, several technologies have been widely used in order to protect water resources from the discharge of many undesirable components. The main objective of this study was to design/scale-up, install, and operate a new hybrid, compact wastewater treatment system (Submerged Membrane Electro-Bioreactor; SMEBR) that would yield an excellent quality effluent, reduce membrane fouling, and improve sludge properties. SMEBR combined three phenomena; membrane filtration, electrokinetics, and biological treatment. Three Phases were performed in this study. In Phase 1 (4 Stages), SMEBR laboratory scale system treating synthetic wastewater operated under different operating conditions to screen out and determine the operating ranges of the technological design parameters. These included the determination of the membrane critical flux and variation of aeration intensity (Stage 1), variation of current density (Stage 2), variation of the electrical zone volume with respect to the total volume of the effective liquid in SMEBR (Stage 3), and variation of hydraulic retention time (HRT) (Stage 4). Phase 2 focused on the scaled-up pilot SMEBR treating raw municipal wastewater. It was divided into 3 Stages where in Stage 1 the pilot SMEBR was designed (Stage 1a), installed (Stage 1b), and operated (Stage 2) in the municipal wastewater treatment plant in the City of l’Assomption (Quebec, Canada) for 7 weeks. A comparative study to the conventioanl MBR was also performed in Stage 2. Stage 3 investigated the relationship between the transmembrane pressure (TMP) and the sludge properties in SMEBR and MBR as well as the interaction among the sludge properties. In Phase 3, the scale-up process was verified using raw wastewater under steady state conditions; and conducted in conjunction to the pilot facility in Phase 2. The design scale-up protocol was also provided for full scale applications. At steady state operation, the removal efficiencies of COD, ammonia (as NH3+-N) and phosphorous (as PO43--P) in SMEBR were 92%, 99% and 99%, respectively. Furthermore, the monitored transmembrane pressure (TMP) had not shown any significant increase which could lead to the conclusion that the membrane fouling was marginal. In SMEBR system, sludge filterability and dewaterability were significantly enhanced by 78% when the mean particle size diameter of the sludge flocs decreased from 69 to 17.5 µm. Specific cake resistance was minimized to 0.15x1014 m/kg (82% reduction). Moreover, SMEBR enhanced sludge settleability by 30% while the sludge volume index (SVI) had decreased from 170 to 119 mL/g. SMEBR significantly improved sludge flocculation while zeta potential had changed from -26.2 to -14.2 mV. Electrodes were found to last for five months before replacement. SMEBR was a “self-purification” system as some of the generated aluminum and major metals were retained and adsorbed on the surface of the electrodes, and small amounts would leave with the effluent or present in the wasted sludge. SMEBR without any additional unit was able to remove undesirable metals from wastewater. High removal rates of Pb (100%), Ni (98.1%), Cu (100%), and Cd (94.6%) were reported. SMEBR energy requirements were less than 1 kWh/m3 with a total energy cost of CAD $0.052/m3. It could be concluded that SMEBR showed superiority in performance over MBR and can be successfully applied to small and large scale wastewater treatment plants.


identifier: Tomaszewskska, Karolina  (2012) Autobiographic Narrative in the Drawings of Napachie and Annie Pootoogook.  Masters thesis, Concordia University.

abstract: In June of 2005, Windows on Kinngait featuring drawings by Annie Pootoogook and Napachie Pootoogook had opened at the Feheley Fine Arts Gallery in Toronto. With this thesis I set out to compare these two art practices, focusing on how each artist approaches issues related to gender and how they tackle the motif of modernity through representations of landscapes (both indoor and outdoor) and objects, all of which convey much about the personal lives of these women.  They will be examined in terms of how space, and the things that fill it, are utilized to convey an idea about personal representation. In order to understand the inventive drawing practices developed by Napachie and Annie, I will trace the changing status of drawing as a medium in relation to the printmaking tradition; I will also introduce some other artists from Kinngait (Cape Dorset) who have explored the tension between traditional and contemporary motifs in their work.   In theoretical terms, I use Hertha Dawn Wong’s scholarship on forms of indigenous autobiography and the postcolonial concept of hybridity (as put forward by Homi Bhabha) to illuminate the 20th-century transformations in Inuit artmaking, as exemplified in the art of Napachie and Annie Pootoogook.


identifier: Szporer, Adam  (2012) E-mail Analysis for Investigators: Techniques and Implementation.  Masters thesis, Concordia University.

abstract: E-mail is a common form of communication in regular use today. As such, it is a normal part of investigating a person or a crime. At present, there are many tools to perform bulk analysis and basic searching, but our research advances the state of the art by applying text mining and unsupervised learning techniques to automate the e-mail analysis process. Our key goals are to group similar e-mails together and to identify the concepts (subjects of discussion) of those e-mail groups. We present several new methods to increase the grouping accuracy: e-mail domain analysis and word pair analysis. We also present a technique for concept analysis. These goals are achieved by integrating our research with the capabilities of Weka, an open-source machine learning suite, and WordNet, a lexical database of the English language. We apply this research to the publicly available Enron e-mail dataset. We verify the results by examining the comparative advantage of each new technique.


identifier: Ben Saleh, Juma  (2012) Network Coding For Star and Mesh Networks.  PhD thesis, Concordia University.

abstract:
This thesis introduces new network coding techniques to improve the file sharing and video streaming performance of wireless star and mesh networks. In this thesis we propose a new XOR based scheduling algorithm for network coding in cooperative local repair. The proposed algorithm commences in three phases. In the first phase, nodes exchange packets availability vectors. These vectors are functions of the probability of correct packet reception over the channel. This is followed by a short period of distributed scheduling where the nodes execute the processing algorithm which tries to minimize the total transmission time. In the third phase, nodes transmit the encoded packets as per the decision of the scheduling algorithm. Simulation results show improvement in system throughput and processing delay for the proposed algorithm. We also study the trade-offs between file sizes, processing delays, number of users and packet availability. In the sequel we display the favorable effects of file segmentation on the performance of the proposed scheduling algorithm. Furthermore, the upper bound on the performance and the analysis of the proposed scheduling algorithm are derived.
Also, in this thesis, the effects of random network coding on code division multiple access/time division duplex (CDMA/TDD) platforms for wireless mesh networks are studied and evaluated. A multi-hop mesh network with single source and multiple receiving nodes is assumed. For reliable data transfer, a Selective Repeat ARQ protocol is used. Two scenarios are evaluated for their efficiency. In scenario 1, but not in scenario 2, random network coding is applied to CDMA/TDD wireless mesh networks. The delay and delay jitter for both scenarios are computed. The study also focuses on the effects of uncontrolled parameters such as the minimum number of neighbors and the network connectivity, and of controlled parameters such as Galois Field (GF) size, packet size, number of Walsh functions employed at each node and the Processing Gain. The analysis and simulation results show that applying random network coding to CDMA/TDD systems in wireless mesh networks could provide a noticeable improvement in overall efficiency.
We also propose a cross layer approach for the Random Network coded-Code Division Multiple Access/Time Division Duplex (RNC-CDMA/TDD) wireless mesh networks. The proposed algorithm selects the number of assigned Walsh functions depending on the network topology. Two strategies of Walsh function assignments are proposed. In the first, nodes determine the number of their assigned Walsh functions depending on the neighbor with the maximum number of neighbors, which we call the worst case assignment.  In the second, nodes determine the number of their assigned Walsh functions depending on the need for each transmission. Simulation results show the possible achievable improvement in the system performance, delay and delay jitter due to cross layer design.


identifier: Linnen, Anne-Marie  (2011) Oxytocin, Stress Reactivity, and Emotional Information Processing: Investigating Two Potential Mechanisms Mediating Oxytocin’s Pro-Social Effects.  PhD thesis, Concordia University.

abstract:
The nonapeptide oxytocin promotes social affiliation in both human and non-human animals. However, the mechanisms underlying this phenomenon require further elucidation. There is increasing evidence that oxytocin is facilitating pro-social behaviour by modulating stress reactivity and social cognitive processes. Two double-blind placebo controlled studies were conducted to further test this theory. Study 1 examined the influence of intranasal oxytocin on the affective and cortisol response to the Yale Interpersonal Stressor (YIPS), a live social-rejection paradigm. Ninety-Six undergraduate students underwent the YIPS, where participants are excluded from two separate conversations by two same-sex confederates. Salivary cortisol levels and mood were repeatedly measured throughout the study. Participants were administered a single dose of intranasal oxytocin (24 I.U.) or placebo prior to beginning the YIPS. The YIPS elicited a significant negative mood response that was more pronounced in females than males. However, no significant cortisol response to the stressor and no sex difference in cortisol reactivity were observed. A significant effect of drug condition on cortisol levels was observed. Participants who were administered oxytocin, relative to placebo, exhibited a decrease in cortisol levels during the YIPS. The study ultimately revealed that oxytocin was effective at reducing cortisol concentrations during an interpersonal challenge.

The aim of study 2 was to investigate the relationship between oxytocin and basic emotional information processing in men and women. Eighty-four participants self-administered 24 I.U. intranasal oxytocin or saline and later completed an assessment of the acoustic startle reflex with varying emotional foregrounds. Oxytocin had no impact on the affective modulation of the startle eyeblink response. Rather, oxytocin significantly diminished the acoustic startle response irrespective of the emotional foreground of pictorial stimuli. The results are consistent with studies showing a dampening effect of intranasal oxytocin on the activation of the amygdala in response to emotional stimuli, and further support oxytocin’s anxiolytic effects on physiological arousal.

Overall, both studies demonstrate that oxytocin modulates the HPA axis during interpersonal challenge, and also the basic startle reflex. It is possible that by dampening these physiological systems, oxytocin is serving to facilitate social approach behaviour.


identifier: Ackerman, Sol  (2012) The Evolutionary Interaction of Intraspecific Competition and Genetic Recombination.  PhD thesis, Concordia University.

abstract:
The reason for the prevalence of sexual reproduction among multicellular eukaryotes is a long-standing unanswered question in evolutionary biology.  It is widely believed that sexual reproduction and the resulting genetic recombination provide a selective advantage by increasing a population’s genotypic variance. However, recombination will only do so when the population is in negative linkage disequilibrium. It has been proposed that if alleles do not contribute multiplicatively to fitness, but instead display a negative epistatic fitness curve, then the population will be in such a state following selection, and sex will be advantageous. However, there is no a priori reason to believe that fitness values should generally be negatively epistatic, as opposed to positive or zero.

In this study, we explore the relationship between contest competition and the maintenance of sexual reproduction. In Chapter 2, we develop a two-locus bi-allelic haploid model to examine the relationship between phenotype, competitive selection, and realized fitness. We assume that competitive ability is directly proportional to the phenotypic value and that the outcome of pairwise competition is dependent on the ratio of competitive abilities of the competing individuals. The stronger competitor does not always win, but it wins more frequently than the weaker competitor does. Using this very simple model, we find that intraspecies competition can lead to frequency dependent changes in genotypic fitness. In addition, competition can result in negative epistasis at the level of realized fitness. This leads to the build-up of negative linkage disequilibrium among the alleles that affect fitness following selection.

In Chapter 3, we explore the effects of competition when the selection is repeated over several generations. We find that the amount of negative linkage disequilibrium builds up continuously in the absence of recombination, and this hinders the progress of selection.  This accumulation of negative linkage disequilibrium is alleviated when recombination is present. We show, using both a numerical modeling approach and through individual-based simulations, that sexual individuals will increase in frequency in a mixed population of sexual and asexual individuals. The selective advantage of recombination is strongest when there is a large difference in competitive ability between genotypes, and when the selected alleles are initially rare.

Finally in Chapter 4, we consider a different mapping of phenotype onto fitness to ensure that our findings are robust. In this case, the outcome of pairwise competition is not determined by the ratio of competitive abilities; instead the stronger competitor always wins. In this case, as expected, there is even  stronger negative epistasis at the fitness level. As a result, we find that advantageous alleles go to fixation at a faster rate when recombining, and sexual individuals increase in frequency when competing against asexual individuals in a mixed population.

Our results indicate that competition can play a significant role in the maintenance of sexual reproduction, and that the advantage of sexual reproduction may not lie in fertility selection, but in viability selection. In a competitive situation, it is better to produce one winner rather than two losers.


identifier: Naffi, Nadia  (2012) Learning to exist in Social Media: A grounded theory about adolescents’ understanding of their interactions in social media, their impact on their everyday life and the behavior they develop to manage them.  Masters thesis, Concordia University.

abstract: In the present context, in which social media is integrating adolescents’ lives, and engaging them in extensive online interactions, it is becoming essential to understand how they mentally construe their practices in social media and whether they are conscious of learning instances happening during their interactions. Such knowledge could enlighten parents about what captivates their children and practitioners about what captivates students’ attention. The literature in the domain points out to a scarcity in educational research focusing on adolescents’ use of social media. Therefore, this study strived to answer two questions. The first question and its sub-questions were: What are adolescents’ mental representations of their practices with social media? How do adolescents explain their behavior in social media, and its consequences on their offline life? And how do they construe their interactions with the social media apps they use inside their networks? The second question and its sub-question were: Are adolescents aware of instances of learning while in social media? And what type of learning do adolescents perceive as possible with social media? The research methodology I adopted consisted of a qualitative interpretive protocol in a grounded theory approach. Nine participants were recruited and engaged in semi-structured interviews and construct analysis interviews. Results show that adolescents had to tackle two challenges to thrive in social media. They had to “learn [to exist]” and “learn to [exist]” in order to ensure an advantageous online presence. Consequently, they were informally learning technical, socialization and managerial skills while using social media.


identifier: Nam, Jungbae  (2012) Heuristic Results for Ratio Conjectures of LE(1, χ).  Masters thesis, Concordia University.

abstract:
Let LE(s, χ) be the Hasse-Weil L-function of an elliptic curve E defined over Q and twisted by a Dirichlet character χ of order k and of conductor fχ. Keating and Snaith introduced the way to study L-functions through random matrix theory of certain topological groups. Conrey, Keating, Rubinstein, and Snaith and David, Fearnley, and Kisilevsky developed their ideas in statistics of families of critical values of LE(1, χ) twisted by Dirichlet characters of conductors ≤ X and proposed conjectures regarding the number of vanishings in their families and the ratio conjectures of moments and vanishings which are strongly supported by numerical experiments.
In this thesis, we review and develop their works and propose the ratio conjectures of moments and vanishings in the family of LE(1, χ) twisted by Dirichlet characters of conductors fχ ≤ X and order of some odd primes, especially 3, 5, and 7 inspired by the connections of L-function theory and random matrix theory. Moreover, we support our result on the ratio conjectures of moments and vanishings of the families for some certain elliptic curves by numerical experiments.


identifier: Sharafat, Mohammad Reza  (2012) Ethernet-Based Communications Network for Teleoperation of Renewable Energy Technologies in Hybrid Mini-Grids.  Masters thesis, Concordia University.

abstract:
Renewable energy technologies (RETs) such as wind and photovoltaic (PV) have great potential for reducing the cost and environmental impact of electricity production in stand-alone power systems (mini-grids). However, due to fluctuating nature of RETs, and the various constraints of diesel power plants, a suitable communication system is required for better coordinating the operation of the various sources and controllable loads so as to increase diesel fuel displacement without compromising the power quality.
A framework for designing and dimensioning a communications network for supervision and control of hybrid mini-grids as well as for choosing the network’s components and interfaces (including the data acquisition systems, modems, network hubs and switches, communications media and channels, etc.) is presented. In this framework, standard technologies and readily available communications units and subsystems are chosen with a view to satisfy the requirements and assumptions. In doing so, the hardware components needed for implementing such a network are identified, and various software pieces are written to integrate all elements of the network. A set of performance measures that are normally used to assess the performance of data communications networks is identified, and their values are obtained via extensive tests.


identifier: Roudgari, Rouzbeh  (2012) Compaction of Soil by Repeated Loading.  Masters thesis, Concordia University.

title: Compaction of Soil by Repeated Loading

abstract:
Abstract

                            Compaction of Soil by Repeated Loading

                                          Rouzbeh Roudgari

Construction of roads is usually made by stripping the top soil (600 to 1000 mm), which often contains organic materials, and replacing it with a layer of subgrade material (crushed stones, well-graded sand). One of the main design requirements is that the subgrade material must be compacted up to a minimum of 95% of the Proctor maximum dry density, as determined from laboratory test results (AASHTO T99). This requirement is usually specified as a norm in any contract document involving field compaction.
Soils can be compacted by repeated, systematic application of high energy using hammer. The imparted energy is transmitted from the ground surface to the deeper soil layer by propagating shear and compression waves types, which force the soil particles into a denser state (R. Massarsch, 1999)
Research in this field has been directed to establish relationships between the water content, the dry density and the compacting effort, the type of soils which allow a higher level of compaction, and to develop field equipment and techniques which would be more effective in performing field compaction. Nevertheless, there are reports to confirm that achieving 95 % of the Proctor maximum dry density in the field compaction is impossible in some cases. The role of the surrounding soils, in particular the underlying layer, in determining the level of compaction, is a paramount parameter in achieving high level of compaction.

This thesis presents a plane-strain numerical model using PLAXIS computer software to simulate shallow compaction of a subgrade layer underlain by a deep deposit of various stiffness levels. The compaction effort is applied by means of repeated loading on the ground and modeled as a static load applied to the soil through a rigid plate having similar properties of roller material. Based on the results obtained in this study, it can be stated that the level of compaction achieved in the field depends on the thickness of the subgrade layer, stiffness of the lower layer, the number of load cycles, and the magnitude of the load applied.
The results of this study are presented in the form of compression curves of the subgrade and lower layer, and accordingly, the level of compaction for a given soil/load/geometry conditions can be predicted. Design guidelines are presented for practitioners.


identifier: Cardoso, Christopher, Ellenbogen, Mark A. and Linnen, Anne-Marie  (2011) Acute Intranasal Oxytocin Improves Positive Self-Perceptions of Personality.  Masters thesis, Concordia University.

creator:
Cardoso, Christopher
Ellenbogen, Mark A.
Linnen, Anne-Marie

abstract: Research suggests the experimental manipulation of oxytocin facilitates positive interactions, cooperation and trust. The mechanism by which oxytocin influences social behavior is not well understood. We explored the hypothesis that oxytocin alters how people perceive themselves, which could be one mechanism by which oxytocin promotes prosocial behavior. In a between-subject, randomized, and double-blind experiment, 100 university students received a 24 I.U. dose of intranasal oxytocin or placebo, and then completed the Revised NEO Personality Inventory (NEO-PI-R) and other self-report measures 90 minutes later. Intranasal oxytocin increased ratings of NEO-PI-R extraversion and openness to experiences (F(1,98) = 4.910, p = .025, partial η2 = .05; F(1,98) = 6.021, p = .016, partial η2 = .06), particularly for the following facets: positive emotions (d = 0.48, p < .05), warmth (d = 0.47, p < .05), openness to values (d = 0.45, p < .05) and ideas (d = 0.40, p < .05), trust (d = 0.44, p < .05) and altruism (d = 0.40, p < .05). Oxytocin had no influence on ratings of negative emotionality, conscientiousness, rejection sensitivity, depression, worry, self-esteem, and perceived social support. The administration of oxytocin improved participants’ self-perceptions of their personality, at least for certain traits important for social affiliation. Increased positive self-referential processing may be one mechanism by which oxytocin promotes positive social behaviors.


identifier: Ghorbani, Zahra  (2012) A Study on Gas Evolving Electrodes under Extreme Current Densities.  Masters thesis, Concordia University.

abstract:
ABSTRACT
A Study on Gas Evolving Electrodes under Extreme Current Densities

Zahra Ghorbani
Electrochemical discharges or electrode effects are used in different fields such as micro-machining, nano-particle production, and surface engineering. Further development and improvement of the different applications of electrochemical discharges require a better understanding of this process. Beyond the critical voltage, an insulating gas film forms around the electrode and discharges take place through the gas film. The stability of the gas film affects the quality of the discharges. The gas film formation is therefore investigated in the present thesis.
The main objective of the current project is to attain a better insight into the gas film dynamics. This goal is achieved through the following approaches: 1. The current-voltage characteristics are studied prior to the gas film formation and then compared with a model developed based on the percolation theory. 2. Since the hydrodynamic forces define the shape and thickness of the gas film, the effect of the hydrodynamic parameters on a gas film are analyzed. Based on the Pi theorem and dimensional analysis, important dimensionless parameters are derived to investigate the gas film formation. 3. Different system configurations are examined to improve the electrochemical discharge activity. Visual observations indicate that stable discharges are obtained by using a covered electrode and applying an offset pulsed voltage.
Key words: Electrochemical discharges, Gas film formation time, Gas film thickness, Gas bubble evolution


identifier: Ravassi, Santiago  (2011) Analysis of the Dynamic Travelling Salesman Problem with Different Policies.  Masters thesis, Concordia University.

format: text text

abstract:
We propose and analyze new policies for the traveling salesman problem  in a dynamic and stochastic environment (DTSP). The DTSP is defined as  follows: demands for service arrive in time according to a Poisson process, are independent and uniformly distributed in a Euclidean region of bounded area, and the time service is zero; the objective is to reduce the time the
 server takes to visit to all the present demands for the first time. We start by analyzing the nearest neighbour (NN) policy since it has the best performance for the dynamic vehicle routing problem (DTRP), a closely related problem to the DTSP. We next introduce the random start policy whose efficiency is similar to that of the NN, and we observe that when the random start policy is delayed, it behaves like the DTRP with the NN policy. Finally, we introduce the partitioning policy, and show that, relative to other policies, it reduces the expected time that demands are swept from the region for the first time.


identifier: Capelovitch, Lawrence  (2011) The True Characters of Criseyde and of Diomede in Chaucer’s Troilus and Criseyde: A Restoration of the Reputations of Two Misunderstood Characters Unjustly Maligned in Literary Criticism.  Masters thesis, Concordia University.

abstract:
The True Characters of Criseyde and of Diomede in Chaucer’s Troilus and Criseyde: A Restoration of the Reputations of Two Misunderstood Characters Unjustly Maligned in Literary Criticism

Lawrence Capelovitch, B.A., B.C.L.

Criseyde and Diomede have been consistently misunderstood and vilified in literary criticism due to a failure in proper analysis of the text and an uncritical acceptance of influences irrelevant to its interpretation.

Criseyde, considered the ultimate female betrayer in literature, was in fact a victim of the betrayals of the four males who touched her life. She was a survivor in time of war who faced her perils with intelligence and dignity while having to make unwelcome choices and decisions under hostile circumstances beyond her control.

Diomede is vilified as an amoral seducer when the text does not support such determination. He is a plain spoken military man, sincere, practical, intelligent, and worthy of Criseyde’s attention, and, ultimately, her love.

This thesis examines Criseyde’s sexuality, one of several leading motivators of her decisions and actions, a subject not generally analyzed in depth, but necessary for a true understanding of the plot and Criseyde’s character.

By focusing microscopically on the text, Chaucer’s brilliance as poet, psychologist, and literary craftsman will become even more apparent than heretofore, and his masterpiece will be appreciated as a tale of ongoing relevance embodying mores no different than as at the present time.


identifier: Mahmood, Ali A.  (2012) Experimental and Computational Assessment of Tailings Binder Matrices for Construction Purposes in Cold Regions.  PhD thesis, Concordia University.

abstract:
Mine tailings are the waste materials of the mining industry. They are typically disposed of in tailings ponds surrounded by tailings dams. This traditional method of disposal has caused severe environmental damage throughout the years. In this study a new approach of sustainable development of tailings is attempted. The study consisted of two phases – experimental and computational. In Phase 1, six different types of tailings are gathered from mines in Eastern Canada and subjected to a series of laboratory tests. Tailings were stabilized using different compositions of binder materials: Portland cement, slag, fly ash along with a new type of binder called Calsifrit. These experiments aimed at verifying the suitability of tailing-binder matrices as road construction material. Furthermore, weathering tests assessed feasibility of using the matrices in cold regions.

In Phase 2 a computational program was developed using the Discrete Element Method to support the engineer’s decision with regards to the application of the binder tailing materials in construction.

Experimental results show that these tailings binder matrices passed the freezing/thawing durability and TCLP tests. In addition, these matrices sustained high compression loads. Using these results, a statistical equation is developed to predict the unconfined compressive strength of the tailings binder matrices. Simulations show that the computer program developed was able to model successfully the unconfined compressive strength and freezing/thawing durability characteristics of the tailings binder matrices.


identifier: Bye, Dorothea  (2012) Intrinsic motivation for cognitive engagement in recently retired adults.  PhD thesis, Concordia University.

abstract:
This thesis examines how need for cognition, the dispositional tendency to engage in and enjoy effortful cognitive activity, predicts subjective well-being over time in older adults in recent retirement. Previous investigations of motivational factors in retirement have been cross-sectional; the original research in the two studies presented here is longitudinal. The goals of this thesis were to position need for cognition within need-based motivational theories, demonstrate its direct and indirect benefits to individuals over the course of two years in early adjustment to retirement, show how individual differences in motivational needs and their satisfaction through appropriate goal-seeking activities predicts emotional well-being for recently retired individuals, and provide suggestions of particular application to both individuals and professionals who are interested in the potential psychological challenges unique to the transition to retirement.
Research data were collected from recently retired adults (mean age = 60 years) who completed four consecutive annual waves of testing as part of the Concordia Longitudinal Retirement Study (2005-2009). Study 1 found that those who were higher relative to lower in need for cognition (i) reported higher levels of positive affect across time; (ii) were more frequently engaged in specific freely chosen activities involving creativity, internet use, and formal volunteering; (iii) scored higher on measures of problem-focused coping and goal re-engagement; and (iv) were more likely to have retired to pursue their own interests than for other reasons. Study 2 revealed that people higher in either need for cognition, competence, or purpose reported higher levels of positive affect at baseline; however, those initially higher in either need for cognition or purpose showed significant drops in positive affect over time relative to their peers’ lower stable affective trajectories. Interaction analyses revealed the counter-intuitive finding that those lowest in both need for cognition and purpose reported a significant increase in positive affect over time, though still having lower affect scores than those with significantly higher initial levels of both need for cognition and purpose who reported stable positive affect during the same period. Both social and motivational implications of these findings are discussed.


identifier: Arabnia, Mohammad  (2012) Aerodynamic Shape Optimization of Axial Turbines in Three Dimensional Flow.  PhD thesis, Concordia University.

abstract: Aerodynamic shape optimization of axial gas turbines in three dimensional flow is addressed. An effective and practical shape parameterization strategy for turbine stages is introduced to minimize the adverse effects of three-dimensional flow features on the turbine performance. The optimization method combines a genetic algorithm (GA), with a Response Surface Approximation (RSA) of the Artifcial Neural Network (ANN) type. During the optimization process, the individual objectives and constraints are approximated using ANN that is trained and tested using a few three-dimensional CFD ow simulations; the latter are obtained using the commercial CFD package Ansys-Fluent. To minimize three-dimensional effects, the stator and rotor stacking curves are taken as the design variable. They are parametrically represented using a quadratic rational Bezier curve (QRBC) whose parameters are directly and explicitly related to the blade lean, sweep and bow, which are used as the design variables. In addition, a noble representation of the stagger angle in the spanwise direction is introduced. The described strategy was applied to optimize the performance of the E/TU-3 axial turbine stage which is designed and tested in Germany. The optimization objectives introduced the isentropic efficiency and the streamwise vorticity, subject to some constraints. This optimization strategy proved to be successful, fexible and practical, and resulted in remarkable improvements in stage performance.


identifier: Fillion, Eric  (2012) The Cinema of the Quiet Revolution: Quebec’s Second Wave of Fiction Films and the National Film Board of Canada, 1963-1967.  Masters thesis, Concordia University.

abstract: Film historians situate the birth of le cinéma québécois in the late 1950s with the emergence – within the National Film Board of Canada (NFB) – of an Équipe française whose Direct Cinema revolutionized documentary filmmaking. The grand narrative of Quebec national cinema emphasises the emancipating qualities of this cinematographic language and insists that it contributed to a collective prise de parole and Quebec’s ascension to modernity. Film historians mythologize the cinema of the Quiet Revolution (1958-1967) by inscribing the fiction films of the 1960s within the trajectory of Direct Cinema. Borrowing from Jocelyn Létourneau, the present thesis uses the concept of community of communication to investigate the documentary-to-fiction transition that accompanied the creation of the NFB’s Production française in the mid-1960s. The argument advanced here is that Quebec’s francophone filmmakers, between 1963 and 1967, distanced themselves from documentary filmmaking – including Direct Cinema – to explore the dramatic form and feature length format. They formed a tightly-knit community of communication whose actions, written works and films explained, legitimized and promoted the notion that Quebecers needed a commercial feature film industry of their own. The most prominent members of the Production française – Gilles Carle, Gilles Groulx and Arthur Lamothe to name but a few – played a preponderant role in this process. They articulated and disseminated an elaborate narrative which allowed them to consolidate their status as auteurs within a post-Duplessis Quebec. The present thesis reconstructs and analyzes the above filmmakers’ narrative to demythologize – and develop an alternative reading of – the cinema of the Quiet Revolution.


identifier: Mohamed, Waleed A.  (2012) Medical Image Registration and 3D Object Matching.  PhD thesis, Concordia University.

abstract:
The great challenge in image registration and 3D object matching is to devise computationally efficient algorithms for aligning images so that their details overlap accurately and retrieving similar shapes from large databases of 3D models. The first problem addressed is this thesis is medical image registration, which we formulate as an optimization problem in the information-theoretic framework. We introduce a viable and practical image registration method by maximizing an entropic divergence measure using a modified simultaneous perturbation stochastic approximation algorithm. The feasibility of the proposed image registration approach is demonstrated through extensive experiments.
The rest of the thesis is devoted to a joint exploitation of geometry and topology of 3D objects for as parsimonious as possible representation of models and its subsequent application in 3D object representation, matching, and retrieval problems. More precisely, we introduce a skeletal graph for topological 3D shape representation using Morse theory. The proposed skeletonization algorithm encodes a 3D shape into a topological Reeb graph using a normalized mixture distance function. We also propose a novel graph
matching algorithm by comparing the relative shortest paths between the skeleton endpoints. Moreover, we describe a skeletal graph for 3D object matching and retrieval. This skeleton is constructed from the second eigenfunction of the Laplace-Beltrami operator defined on the surface of the 3D object. Using the generalized eigenvalue decomposition, a matrix computational framework based on the finite element method is presented to compute the spectrum of the Laplace-Beltrami operator. Illustrating experiments on two standard
3D shape benchmarks are provided to demonstrate the  feasibility and the much improved performance of the proposed skeletal graphs as shape descriptors for 3D object matching and retrieval.


identifier: Mckearney, Dennis Wade  (2011) An Experience in Literary Translation Translation and Commentary on Jean Barbe’s Le travail de l’huître.  Masters thesis, Concordia University.

abstract: Through the translation of and commentary on Jean Barbe’s short novel, Le travail de l’huître, this thesis seeks to explore some of the issues that arise during the process of translating a literary text. Based on Umberto Eco’s theories on interpretation, one fundamental premise is that translation is first and foremost an act of reading, and part of the translator’s task consists in learning how to read for the work of translation and where such reading actually begins. Antoine Berman provides the second fundamental premise, which is the requirement for the translator to develop a consciousness of him or herself as a translating subject whose specificity inescapably influences the translation process and the product of that process. For the more detailed work of textual analysis, the thesis relies first on the work scholars such as Jonathan Culler, for an understanding of the literary nature of this text, and Gérard Genette and his work on textual borders. The final translation of Le travail de l’huître was also produced in light of the work of many practising translators, whose thoughts and practices provided an interesting comparison and contrast with the work of the theorists.


identifier: Memarian, Ramin  (2012) Phytoremediation of Soil containing Mixed Contaminants.  PhD thesis, Concordia University.

abstract:
Phytoremediation of Soil containing Mixed Contaminants

Ramin Memarian, Ph.D.
Concordia University, 2012

This study investigated the application of surfactants and chelates to enhance the removal of mixed contaminants [Cd (II), Pb (II) and used engine oil] from a sandy soil cultivated with Indian mustard plants. For chelate additives, EDTA (Ethylenediamine tetraacetic acid) was found to be more efficient than EDDS (Ethylenediamine disuccinic acid) in increasing the accumulation of metal contaminants Pb (II) in the plants. EDTA was also more capable of removing the used engine oil through rhizodegradation than EDDS. EDTA caused a sharper decrease in basal soil respiration (BSR) than EDDS, indicating that the former was much more toxic to the microbes.
For surfactant additives, the results showed that Triton X-100 and Tween 80 at concentrations higher than their critical micellar concentration enhanced phytostabilization of Pb (II). The application of Tween 80 resulted in an increase in phytoremediation of Pb (II). At the same concentrations, Tween 80 was more effective than Triton X-100 in facilitating rhizodegradation of the used engine oil. Soil basal microbiological respiration tests showed that the application of Tween 80 resulted in an increase in BSR.  These tests indicated that the lower concentration of Triton X-100 had a slightly positive effect on BSR, whereas at higher concentrations, it was inhibitory to the microbes.
Empirical phytoremediation models linked to the removal of the heavy metals from the soil were formulated in the study. The two first order kinetic models were able to describe the leaching process for both Cd (II) and Pb (II). The models also revealed that the uptake of Pb (II) and Cd (II) were well described by the Freundlich type model, in the presence of surfactants. On the other hand, in the presence of chelates the uptake of Pb (II) and Cd (II) was found to follow the Langmuir type model.  According to the leachability index (LI) determined in the tests, all surfactants tested can be   considered   as safe additives for enhancing phytoremediation. Compared to Triton X-100, Tween 80 resulted in lower diffusivity of metals tested and higher values of LI indicating that this surfactant was also safer from the point of view of reducing ground water pollution. Compared to EDTA, EDDS resulted in higher values of LI, which is desirable.


identifier: Yu, Zhun  (2012) Mining Hidden Knowledge from Measured Data for Improving Building Energy Performance.  PhD thesis, Concordia University.

abstract:
Nowadays, building automation and energy management systems provide an opportunity to collect vast amounts of building-related data (e.g., climatic data, building operational data, etc.). The data can provide abundant useful knowledge about the interactions between building energy consumption and its influencing factors. Such interactions play a crucial role in developing and implementing control strategies to improve building energy performance. However, the data is rarely analyzed and this useful knowledge is seldom extracted due to a lack of effective data analysis techniques.
In this research, data mining (classification analysis, cluster analysis, and association rule mining) is proposed to extract hidden useful knowledge from building-related data. Moreover, a data analysis process and a data mining framework are proposed, enabling building-related data to be analyzed more efficiently. The applications of the process and framework to two sets of collected data demonstrate their applicability. Based on the process and framework, four data analysis methodologies were developed and applied to the collected data.
Classification analysis was applied to develop a methodology for establishing building energy demand predictive models. To demonstrate its applicability, the methodology was applied to estimate residential building energy performance indexes by modeling building energy use intensity (EUI) levels (either high or low). The results demonstrate that the methodology can classify and predict the building energy demand levels with an accuracy of 93% for training data and 92% for test data, and identify and rank significant factors of building EUI automatically.
Cluster analysis was used to develop a methodology for examining the influences of occupant behavior on building energy consumption. The results show that the methodology facilitates the evaluation of building energy-saving potential by improving the behavior of building occupants, and provides multifaceted insights into building energy end-use patterns associated with the occupant behavior.
Association rule mining was employed to develop a methodology for examining all associations and correlations between building operational data, thereby discovering useful knowledge about energy conservation. The results show there are possibilities for saving energy by modifying the operation of mechanical ventilation systems and by repairing equipment.
Cluster analysis, classification analysis, and association rule mining were combined to formulate a methodology for identifying and improving occupant behavior in buildings. The results show that the methodology was able to identify the behavior which needs to be modified, and provide occupants with feasible recommendations so that they can make required decisions to modify their behavior.


identifier: Krynitzki, Sara  (2012) Diasporas and the Foreign Policy Agendas of their Host States.  Masters thesis, Concordia University.

abstract:
The purpose of this thesis is to answer the following set of interrelated research questions: do diasporas influence the foreign policy agendas of their host countries regarding their home countries? If so, when do they do it and how do
they do it? In this thesis, I develop a primary explanation and an alternative explanation to test against the evidence I find in my case studies to determine which explanation is the more compelling explanation for the research questions
posed. My primary explanation is that host country foreign policymakers are likely to place a diaspora’s home country policy issue onto the host country foreign policy agenda as a result of a diaspora’s electoral influence. My
alternative explanation is that host country foreign policymakers are likely to place a diaspora’s home country policy issue onto the host country’s foreign policy agenda if the diaspora effectively frames the issue in ways that engage and appeal to policymakers. As case studies, I focus on the Sri Lankan Tamil diasporas in Britain and in Canada, and their respective roles in influencing the foreign policy agendas of Britain and Canada regarding the Sri Lankan civil war. After testing the explanations against the evidence in the case studies, I determine that the more compelling explanation is that diasporas influence the foreign policy
agendas of their host countries regarding their home countries when they effectively frame the issues in ways that engage and appeal to policymakers.


identifier: Nargis, Syeda Laila  (2012) Communicating urban density: Assessing the challenges and opportunities in the use of 3-D representation for public participation in planning.  Masters thesis, Concordia University.

abstract:
Abstract
Communicating urban density: Assessing the challenges and opportunities in the use of 3-D representation for public participation in planning

Syeda Laila Nargis

The issue of urban densities is central for cities that aim at reducing their environmental footprints. As many cities are devising intensification policies that would significantly alter the spatial form, the demand for public participation in the planning process becomes more pressing. To meet this demand, specialists employ three dimensional (3-D) technologies that allow effective communication with non-specialists. Urban density is a complicated notion which is difficult to communicate to non-specialists.

The purpose of the present study is to identify some of the difficulties faced by specialists and non-specialists that wish to exchange a dialogue over urban density. It focuses on perception and cognition problems regarding density in 3-D digital representation. It endeavors more specifically to understand whether an active engagement with digital 3-D models displaying density changes favors a better cognition of specialists and non-specialists including those who come to the experiments with preconceived (false) conceptions.

The results show that there is a significant difference between active and passive engagement with 3-D models. The success rate of participants’ actively interacting with the digital model is higher than that of their passive counterparts. By stressing the fact that an active engagement with 3-D digital modes favours a better cognition of urban density this study can contribute to the improvement of the methods and tools used to encourage the public participation to the planning debates pertaining to density.


identifier: Ahmed, Marwa Hussein  (2012) Assessment of Activities’ Criticality to Cash-Flow Parameters.  Masters thesis, Concordia University.

abstract:
Cash flow modeling is a very useful financial management tool that contractors use to run a sustained business. Contractors manage multiple activities within a single project. The activities’ start times are the inherent variables which determine the values of periodical negative cumulative balances and the other cash-flow parameters of cash flow model. Since the start times of activities vary while the dependency is maintained, in any given schedule the maximum value of the negative cumulative balance varies, as do the values of the other cash-flow parameters. This work reveals a system that can identify those activities that have the most influence on cash flow.
The Monte Carlo Simulation technique has been employed here to generate schedules and their associated cash flow models for a case study by randomly specifying the activities’ start times between their respective early and late start times. Uniform discrete probability distributions are assumed for the activities’ start times, with the minimum and maximum values representing the early and late start times, respectively. In addition to the randomness of the activities’ start times, the simulation model considered the stochastic nature of the periodic cash in and cash out transactions in the cash flow model by adjusting their values to account for the impact of 43 qualitative factors identified in an earlier study.
The @RISK commercial software was used to implement the simulation of the cash flow model built in an MS-Excel environment. Upon completing the specified number of runs, @RISK displays the probability distributions for the cash-flow parameters including the financing costs, maximum negative cumulative balance, project duration, and project profit.
In addition, three scenarios are defined; each incorporating a different number of qualitative factors which impact the project cash inflow and cash outflow transactions. Scenario I incorporates none, Scenario II incorporates six factors impacting cash inflow transactions and nine factors impacting cash out flow transactions, and scenario III incorporates all of the qualitative factors that impact cash inflow and cash outflow transactions. Moreover, the ranges of the activities’ start times have been extended by supplementing the total floats with extension increments for the three scenarios.
The results are presented and analyzed based on the three scenarios. The activities’ criticality to cash-flow parameters is assessed by evaluating the number of times a given activity determined a particular cash-flow parameter over the number of runs. This criticality measurement offers project managers very useful criteria with which to identify the activities that are most urgent to be completed on time.


identifier: Sha, Yuqing  (2012) Short Term Momentum: Role of Investor Sentiment in Return Formation.  Masters thesis, Concordia University.

abstract: Using transaction level data spanning across eighteen years over 1993 to 2010, we show that heavily bought stocks or heavily sold stocks display persistence in buy and sell order respectively. We show that over one trading day horizon, the persistence is strong enough to generate economically significant return. CAPM market factor, Fama-French Size and Book to Market factors, as well as Carhart’s momentum factor do not explain these results. However, the returns can be at least partially explained by investor sentiment variables and macroeconomic condition variables such as term and default spread and business cycle.


identifier: Shepherd, Tamara  (2012) Persona Rights in Young People’s Labour of Online Cultural Production: Implications for New Media Policy.  PhD thesis, Concordia University.

abstract:
This thesis rests on the argument that the social internet as a commercial space is basically subtended by the appropriation of user labour, in the form of what has come to be called “user-generated content” or UGC. Especially it seems for younger people engaged in the labour of UGC, online content creation also inculcates them into an economy of creative labour. As a kind of apprenticeship for more formal creative industry careers, UGC creates value for both online platforms and for the users’ development of a branded online identity.

Identity work – which in this investigation mainly entails negotiating dimensions of age and gender (and to a lesser extent, class, race and ability) – constitutes an integral part of the value of UGC for individual careers as well as for commercial platforms, but also for the broader civic reverberations of online cultural production. Networked production and sociality are becoming more and more central to conceptions of contemporary citizenship alongside those of economic agency. To this end, the commercial imperatives of the social internet that tend to determine persona rights online, namely rights around privacy and intellectual property, demand re-evaluation in light of UGC as a labour practice.

Legislative protections for Canadians’ persona rights are currently under debate, but internet regulation faces a number of challenges and thus should be accompanied by other strategies for bolstering people’s persona rights online. Ultimately, this thesis seeks to enumerate recommendations for policymaking around privacy and intellectual property in UGC environments, but also to suggest ways for young people to retain their persona rights while engaging in the UGC labour of online cultural production.

The research questions guiding this thesis follow from its central goal of re-evaluating internet regulation from the point of view of UGC as apprenticeship labour. As such, the overarching research question asks, how might new media policy approach the issue of user labour in online cultural production to protect persona rights? This question invites an answer in the form of recommendations for policymakers, but the structural constraints of policy as a top-down protective mechanism requires alternative modes of addressing persona rights issues from the bottom-up, for instance in media and policy literacy initiatives as well as in participatory technology design. These conclusions stem from the project’s overview of policy research and scholarly work, but also from its analysis of four case studies that illustrate some of the activities and experiences of users in their early-20s, who are deeply engaged in the labour of UGC.


identifier: Beddard, Carol  (2012) Motivating Adult Students Taking a Basic Algebra Course in a University Setting.  Masters thesis, Concordia University.

abstract:
Abstract
Motivating Adult Students taking a Basic Algebra Course in a University Setting
Carol Beddard
Understanding the motivation of students learning mathematics and using this understanding to strengthen motivation can improve mathematics instruction for students, especially students who may dislike math.  Motivation is modeled as arising from an interaction of needs, goals and dimensions of the self, resulting in behavior that is regulated by feedback and external factors.
The study uses a Conjecture-Driven design in the teaching situation of MATH 200 – Fundamental Concepts of Algebra which is a required course for many students.  That they have to take a basic algebra course at the university level is indicative of some previous difficulties with mathematics which in turn can be linked to negative affect towards math.  The conjecture was that motivation would be lacking among this group of students but that a class that is taught from a motivational standpoint would result in better attitudes towards math.  Based on an a priori profile of motivational characteristics, the hypothetical student, the course was taught with the aim of improving motivation.  Observations, course evaluations, a questionnaire and a survey were used to:  (1) create a profile of observed motivational characteristics, the realistic student, and (2) to describe the effect of the course on student motivation.
It was found that a classroom that addressed students’ needs for autonomy, competence and relatedness, promoted an understanding of why a procedure was used (rather than just how to apply the procedure), and that at all times respected the dignity of students, was motivational.  In this classroom, the students reported improved affect towards mathematics across the dimensions of emotions, attitudes, beliefs and values.


identifier: Sarkis, Joyce  (2012) The Cognitive, Attitudinal, and Behavioural Responses of the Elderly to Print DTC Prescription Drug Advertising.  Masters thesis, Concordia University.

abstract:
Pharmaceutical companies have adopted a pull marketing strategy of prescription drugs as part of their marketing mix. This approach referred to as Direct-To-Consumer Advertising (DTCA) where drugs are directly advertised to the consumer through mass media, has been the topic of an ongoing debate. While advocates of DTCA defend its educational value, opponents question its safety, especially when addressing a market segment presumed to be vulnerable (i.e., the elderly).
     Based on previous research that demonstrated the dependence of advertising message persuasiveness on a number of individual factors, this thesis investigates the elderly’s responses to DTCA, across variations in their prescription drug use, health status, and cognitive abilities. How do users (vs. non-users) of prescription drugs, and older consumers with high (vs. low) cognition, differ in their post-exposure attitudes towards the ad and advertised brand, in their ad recognition, and behavioural intentions?
     The findings suggest that prescription drug users are more receptive of DTCA and more willing to act in response to it. However, all participants regardless of their health status were resistant to changing their doctor, if he/she refused to prescribe the advertised drug to them. Also, consumers with a high cognition level better recognized the ad’s claims, engaging in a benefit/risk trade-off in their processing of the ad information. The results further suggest that sufferers who do not use a prescription drug do not differ in their post-ad-exposure attitudes and behavioural intentions than non-sufferers. Finally, managers are advised to carefully design their ads taking into consideration the elderly’s cognitive deficiencies.


identifier: Fong, Deanna Marie  (2012) A Taxonomy of Ghosts.  Masters thesis, Concordia University.

title: A Taxonomy of Ghosts

abstract: A Taxonomy of Ghosts is a collection of poems based on the journals of Archibald Menzies (1754-1842), Scottish surgeon, botanist and naturalist outfitted to the exploration voyage of the HMS Discovery and Chatham, under the command of Captain George Vancouver from 1791 to 1795. Using kernels of the original journal text as a point of departure, these poems employ a variety of techniques to intervene and expand them outward; they venture into the less documented territory of Menzies’ domestic life, turning the botanist’s keen observational gaze toward matters of the heart—love, loss and longing. The second segment of the book is the poet-as-speaker’s reflection on her encountering both the Vancouver voyage and the coastal landscape that bears its imprint. In dialogue with both the original journals and other historical and literary representations of the Vancouver voyage, A Taxonomy of Ghosts is a meditation on the powerful force of names and naming, the representation of history and one’s own personal connection to the past.


identifier: Nerguizian, Vahé  (2012) Non-Destructive Bio-Assay of Single Living Cell.  PhD thesis, Concordia University.

abstract:
For more than a decade, researchers are trying to find out practical commercial tool for particle/cell detection and characterization with portable, low cost, specific and sensitive characteristics. The advance of Micro Electro Mechanical Systems (MEMS) and microfluidic technologies opened a major challenge for a large number of researchers, industrial health and bio companies to invest their time and budget into the avenue of point of care health instruments or devices helping the early detection of cancer cells within the human blood via circulating malignant cells.
Actual existing commercial flow cytometer that detects and identifies the type and size of cells are costly, time consuming and need the assistance of highly qualified operators. Moreover, in certain research activities, micro cytometers are investigated and assessed with different detection techniques such as optical, impedance spectroscopy, electromagnetic spectroscopy and many other techniques.
The aim of this research is to investigate an innovative mechanism that enables to characterize, identify and differentiate among various living cells including malignant tumor cells through the use of the electromagnetic energy detection technique. Cells are spatially centered in a microfluidic channel through dielectrophoresis technique then detected and characterized by measuring and interpreting the RF signal transmission of the cells passing one by one through the interrogation region in the microchannel.
	The outcome of this research might help the clinical end user to gain certain important information about the condition of the patient, establish personalized treatment or track the effect of a treatment. Detection and counting of tumor cells may help identification of early stages of illness and help patient with early care that may significantly cut the overall cost of cancer management.


identifier: Kilicoglu, Haci Halil  (2012) Embedding Predications.  PhD thesis, Concordia University.

title: Embedding Predications

abstract:
Written communication is rarely a sequence of simple assertions.  More often, in addition to simple assertions, authors express subjectivity, such as beliefs, speculations, opinions, intentions, and desires. Furthermore, they link statements of various kinds to form a coherent discourse that reflects their pragmatic intent. In computational semantics, extraction of simple assertions (propositional meaning) has attracted the greatest attention, while research that focuses on extra-propositional aspects of meaning has remained sparse overall and has been largely limited to narrowly defined categories, such as hedging or sentiment analysis, treated in isolation.

In this thesis, we contribute to the understanding of extra-propositional meaning in natural language understanding, by providing a comprehensive account of the semantic phenomena that occur beyond simple assertions and examining how a coherent discourse is formed from lower level semantic elements. Our approach is linguistically based, and we propose a general, unified treatment of the semantic phenomena involved, within a computationally viable framework. We identify semantic embedding as the core notion involved in expressing extra-propositional meaning. The embedding framework is based on the structural distinction between embedding and atomic predications, the former corresponding to extra-propositional aspects of meaning. It incorporates the notions of predication source, modality scale, and scope. We develop an embedding categorization scheme and a dictionary based on it, which provide the necessary means to interpret extra-propositional meaning with a compositional semantic interpretation methodology. Our syntax-driven methodology exploits syntactic dependencies to construct a semantic embedding graph of a document. Traversing the graph in a bottom-up manner guided by compositional operations, we construct predications corresponding to extra-propositional semantic content, which form the basis for addressing practical tasks.  We focus on text from two distinct domains: news articles from the Wall Street Journal, and scientific articles focusing on molecular biology. Adopting a task-based evaluation strategy, we consider the easy adaptability of the core framework to practical tasks that involve some extra-propositional aspect as a measure of its success. The computational tasks we consider include hedge/uncertainty detection, scope resolution, negation detection, biological event extraction, and attribution resolution.  Our competitive results in these tasks demonstrate the viability of our proposal.


identifier: Khoshnasib Fallah, Kamran  (2012) Data Encryption and Hashing Schemes for Multimedia Protection.  Masters thesis, Concordia University.

abstract:
There are millions of people using social networking sites like Facebook, Google+, and Youtube every single day across the entire world for sharing photos and other digital media. Unfortunately, sometimes people publish content that does not belong to them. As a result, there is an increasing demand for quality software capable of providing maximum protection for copyrighted material. In addition, confidential content such as medical images and patient records require high level of security so that they can be protected from unintended disclosure, when transferred over the Internet. On the other hand, decreasing the size of an image without significant loss in quality is always highly desirable. Hence, the need for efficient compression algorithms.

This thesis introduces a robust method for image compression in the shearlet domain. Motivated by the outperformance of the Discrete Shearlet Transform (DST) compared to the Discrete Wavelet Transform (DWT) in encoding the directional information in images, we propose a DST-based compression algorithm that provides not only a better quality in terms of image approximation and compression ratio, but also increases the security of images via the Advanced Encryption Standard. Experimental results on a slew of medical images illustrate an improved performance in image quality of the proposed approximation approach in comparison to DWT, and also demonstrate its robustness against a variety of tests, including randomness, entropy, key sensitivity, and input sensitivity. We also present a 3D mesh hashing technique using spectral graph theory. The main idea is to partition a 3D model into sub-meshes, followed by the generation of the Laplace-Beltrami matrix of each sub-mesh, and the application of eigen-decomposition. This, in turn, is followed by the hashing of each sub-mesh using Tsallis entropy. The experimental results using a benchmark 3D models demonstrate the effectiveness of the proposed hashing scheme.


identifier: St-Laurent, Alexander Rock  (2012) Barbotte.  Masters thesis, Concordia University.

title: Barbotte

abstract:
This project recreates the real-life events surrounding
Harry Davis’s murder in July of 1946. Davis, the kingpin of
Montreal’s underworld, functioned as an intermediary
between the city’s organized crime and corrupt city
officials. His murder by fellow mobster Joe Miller provoked
a period of civic and legal reform, starting with the
hiring of the incorruptible Pacifique “Pax” Plante as Chief
of police and head of the special unit known as the
Morality Squad.
 The unit had been designed to take down the city’s
organized crime, but served as little more than a pretense
to appease upright taxpayers. After decades of cooperation
and payoffs between the police, politicians and the
underworld, civic unrest lead Plante to step in to cleanse
both the city and the police department of immoral and
illegal activities, vowing to shine a light on the “Feydeau
farce” that was the judicial system.
 Plante’s hiring, however, soon proved to be yet another
pretense, as he was quickly relieved of his position,
restoring the balance of power to corruption and
profiteering.


identifier: De Stefano, Jacqueline  (2012) The Generational Divide: Understanding Work Centrality, Organizational Commitment and Communication Satisfaction.  Masters thesis, Concordia University.

abstract: Generational differences in the workforce have become topics of interest in popular management journals, which are keen to use anecdotes and stereotypes to make recommendations to their readers. However, little empirical research has been done on this topic, especially as it pertains to work/life balance, communication satisfaction and organizational commitment. The current study analyzes the potential generational differences in three industries: banking, teaching and marketing and media in a sample of 138 active members of the workforce from three different generations: Baby Boomers, Generation X and Millennials. Affective and normative commitment, communication satisfaction and work centrality were the outcome variables of this study. Results from this study revealed that only work centrality was significantly different among the surveyed generations. Affective commitment, normative commitment and communication satisfaction showed no differences among Baby Boomers, Generation X and Millennials. Various age constructs were also used in this study, including subjective age, perceived relative age and chronological age. Results revealed that all age constructs were related to affective commitment, communication satisfaction, with subjective age having the strongest relationship to the outcome variables. Normative commitment and work centrality were not related to age measures. Implications for managers and future research were discussed.


identifier: Lan, Ruomeng  (2012) The Minimizer of the Dirichlet Integral.  Masters thesis, Concordia University.

title: The Minimizer of the Dirichlet Integral

abstract: In this thesis, we consider the minimizer of the Dirichlet integral, which is used to compute the magnetic energy. We know that the Euler equations describe a motion of an inviscid incompressible fluid. We show that the infimum of the Dirichlet integral, by the action of area-preserving diffeomorphisms, is a stream function corresponding to some velocity field, which is a solution to the stationary Euler equation. According to this result, we study the properties and behaviors of the steady incompressible flow numerically. We utilize three distinct numerical methods to simulate the minimizer of the Dirichlet integral. In all cases the singularity formation was observed. Every hyperbolic critical point of the original function gives rise to a singularity of the minimizer.