identifier: Mustafayev, Elvin  (2016) The impacts of work self-efficacy and person-organization fit on employee withdrawal behaviours and job embeddedness under the pay for performance system: An empirical study.  Masters thesis, Concordia University.

abstract: Purpose - This study aims to investigate sales agents’ job embeddedness and withdrawal behaviour by using the Conservation of Resources (COR) as an overarching theoretical framework. It seeks to contribute to better the framework of this model by considering work self-efficacy and person-organization fit as predictors of sales agents’ job embeddedness and withdrawal behaviour under pay for performance system. In particular, it is hypothesized that both work self-efficacy and person-organization fit are negatively correlated with withdrawal behaviours, which include turnover, absenteeism and lateness attitude, and are positively associated with job embeddedness under the pay for performance system. Design/methodology/approach - An online survey was conducted with a total of 105 sales agents in the USA (42 women). Findings - The research reveals findings in favour of the hypotheses that work self-efficacy and person-organization fit are both negatively associated with and significant predictors of turnover intention. However, they are positively and significantly correlated with lateness attitude, which is the opposite of what was hypothesized. Self-efficacy is the only variable that is negatively and significantly related to absenteeism, while the person-organization fit is the only variable positively and significantly related with job embeddedness.


identifier: Kim, Soyoung  (2016) On the Semantics of Queries over Graphs with Uncertainty.  Masters thesis, Concordia University.

type: Thesis NonPeerReviewed

abstract: We study the semantics of queries over uncertain graphs, which are directed graphs in which each edge is associated with a value in [0,1] representing its cer- tainty. In this work, we consider the certainty values as probabilities and show the challenges involved in evaluating the reachability and transitive closure queries over uncertain/probabilistic graphs. As the evaluation method, we adopted graph re- duction from automata theory used for finding regular expressions for input finite state machines. However, we show that different order of eliminating nodes may yield different certainty associated with the results. We then formulate the notion of "correct" results for queries over uncertain graphs, justified based on the notion of common sub-expressions, and identify common paths and avoid their redundant multiple contributions during the reduction. We identify a set of possible patterns to facilitate the reduction process. We have implemented the proposed ideas for answering reachability and transitive closure queries. We evaluated the effectiveness of the proposed solutions using a library of many uncertain graphs with different sizes and structures. We believe the proposed ideas and solution techniques can yield query processing tools for uncertain data management systems.


identifier: Cavaliere, Elizabeth Anne  (2016) Mediated Landscape/Mediating Photographs: Surveying the Landscape in Nineteenth-century Canadian Topographical Photography.  PhD thesis, Concordia University.

abstract: The photographs produced as part of Canadian topographical and geological surveys between 1858 and 1890 have teetered between readings of document and art. This is further complicated by the archival and museum collections into which they have been absorbed, institutional divisions that reinforce the distinctions between historical document and aesthetic artwork. This thesis addresses such unresolved tensions by considering topographical photographs as both mediated and mediating in their ability to bridge and accommodate a nexus of antithetical readings – maker and viewer, authorial intent and collective imagination, art and document, subjective and objective, land and landscape. The survey work of four photographers is examined: Humphrey Lloyd Hime (1833-1903) on the 1858 Assiniboine and Saskatchewan Exploring Expedition; Benjamin F. Baltzly (1835-1883) on the 1871 Geological Survey of Canada expedition; Alexander Henderson’s (1831-1913) commissions to document the structures of the Intercolonial Railway, the Quebec, Montreal, Ottawa & Occidental Railway, and later as superintendent of photographs for the Canadian Pacific Railway; and Charles George Horetzky (1838-1900) on various expeditions between 1871 and 1877 with the Canadian Pacific Railway Survey. In each case study, the photographs are understood as oscillating between functions and readings of science and art. Special attention is given to the texts left behind by each photographer. Biographical histories are compiled from archival findings in order to develop a network of relationships. The circulation of the photographs in scientific, governmental, artistic, and popular arenas is also traced. This thesis argues that by studying nineteenth-century Canadian survey photography within art history what emerges is the foundation of a mutually influential relationship between not only photography and painting, but also between art and document, and the Picturesque and the Romantic. My intention is to demonstrate that while survey photographs can reveal historical context, they also reveal art historical context in the ways that land becomes a landscape through visual representation.


identifier: Thirunavukarasu, Asok  (2016) Protocol for Low Energy Houses for Northern Canadian Regions.  Masters thesis, Concordia University.

abstract: Despite Northern Canada’s unique environmental loads and challenges, homes are based on standards developed for the South. This thesis presents the development of a protocol for low energy homes (LEH) for northern Canada. The protocol integrated the building envelope system with passive solar design strategies for northern Canada. This research identified areas of interest and challenges for the region through literature review, interviews with occupants and builders, and data analysis of 1744 homes in the NWT from the EnerGuide energy rating service (ERS) database. A reference home was modelled to study design parameters such as thermal resistance values of building assemblies, window-wall ratios, thermal mass, BIPV/T system’s capacity, night window shutters, shading schedules, and ventilation rates. Optimization of solar design strategies can achieve a 49% energy savings. This finding gives policy makers a methodology for displacing housing energy demand by promoting design strategies to builders such as better orientation and optimizing window-wall ratios for solar heat gains, and integrating thermal mass in floors and on interior walls. Based on the findings of this research, a protocol for low energy homes for the North is presented which includes key relevant standards, guidelines, criteria and verification methods that are to be met through the design, construction, and operational stages. The Protocol anticipates and addresses significant related challenges of the remote region to promote a delivery system that involves all stakeholders, reduces delays and cost overruns.


identifier: Najafi Nejad Nasser, Azita  (2016) Two-Phase Bubble Flow Modelling for Restoration of Eutrophic Lakes.  PhD thesis, Concordia University.

abstract:
For the remediation of eutrophic, anoxic lakes, this thesis considers artificial circulation as a technique by introducing air bubbles into the lake water, which has the advantage that no chemical substances will be added to the lake water. This study aims to improve the understanding of the hydrodynamic behaviour of water elements and air bubbles in a water body subject to aeration, and to investigate optimal aeration schemes for prevention of sedentary conditions and improvement of the anoxic conditions in eutrophic lakes.
A computational fluid dynamics (CFD) analysis of two-phase flow was performed using two different types of model domains: a cylindrical bubble column; and lakes. Predictions of the flow field are obtained from numerically solving the Reynolds-averaged continuity and momentum equations, using the Eulerian-Eulerian multiphase method. The CFD results are validated through a comparison of the predictions with available experimental measurements of the quantities made from a laboratory water tank.
Subsequently, the response of water and bubble motions to a selection of bubble size, air flow rate, and spatial configurations of injection was investigated. Using the results from these simulations, the beneficial effects of aeration on the enhancement of oxygen concentrations in the water column are analysed.
The results show that a proper solution for bubble columns is crucially dependent on the correct modelling of interphase forces and turbulence models. The consideration of the effect of interfacial forces has improved the results, especially at larger distances from the centreline of the model domain.
Oxygen is shown to transfer to water across bubble interfaces as the bubbles rise to the water surface. Oxygen transfer also occurs across the air-water interface at the free surface as a result of turbulence induced by bubble motions and water circulation.
Many independent variables have influence on the bubble flow field. The first set of variables was related to air injection, including bubble size, initial velocity, and air flow rate. The second set of variables is diffuser variables, including the number of ports, port diameter or diffusion area, spacing between adjacent ports, port angle with the horizontal, and elevation of ports above the bottom.
It has been demonstrated that a properly installed aeration system in a lake can possibly halt and eventually reverse anoxic condition. De-oxygenated bottom water is exchanged with highly oxygenated surface water. The opening of ports should be mounted at a certain height from the bottom. Specifically, the optimal height is shown to be 0.3 m for shallow lakes with a maximum depth of 2 m. Port spacing should be approximately equal to the maximum depth. This installation prevents re-suspension of bottom sediments while it creates full circulations around the injector. It reduces dead zones between two adjacent injectors and produces stronger downward flows. The installation induces the dispersion of air and increases oxygen transfer rate in water. The oxygen concentration is continuously increased with time and reaches a steady state. Thus, an aeration system can possibly halt and eventually reverse anoxic condition. This thesis has demonstrated that computer modelling of aeration has the potential to improve our understanding of complex bubbly flow processes through systematic simulations.


identifier: Saha, Shuvasish  (2016) Analog Pre-distortion Circuit for Simultaneous Suppression of Third and Fifth Order Intermodulation Distortion in Broadband Radio-over-Fiber Systems.  Masters thesis, Concordia University.

abstract:
ABSTRACT

Analog Pre-distortion Circuit for Simultaneous Suppression of Third and Fifth Order Intermodulation Distortion in Broadband Radio-over-Fiber Systems

                                  Shuvasish Saha

Rapid advance in wireless technologies coupled with the exponential increase in use of high bandwidth devices and applications have made it necessary to develop high capacity wireless transmission networks. Design of robust and cost-effective wireless signal transmission systems has become of paramount importance to keep up with the breakneck pace of wireless access demand, especially keeping in mind the future of massive multiple-input and multiple-output (MIMO) wireless. Radio-over-Fiber (RoF) transmission systems are at the forefront of the research topics being investigated right now as a possible solution to keep up with this exploding demand for wireless network access.

Based on optical subcarrier modulation, RoF transmission systems combine the use of both optical fiber and radio transmission. Optical fibers are low cost. They are lightweight and suffer from low loss. They provide extremely high capacity and immunity from electromagnetic interference. Radio transmission over fiber makes it easy to assemble Remote Radio Units (RRUs) at antenna towers. However, RoF is an analog optical transmission system and it is susceptible to non-linear distortions caused by all the inline functional optical and electrical components. In case of front-haul RoF transmission systems of wireless access networks, two key specific functions: RF power amplification and optical subcarrier modulation, are the main contributors to the production of non-linear distortions. Non-linear distortions consist of harmonic distortions (HDs) and intermodulation distortions (IMDs). It is essential to suppress these distortions because they can introduce crosstalk if they fall in the passband of RF signals.

In this thesis, the use of analog pre-distortion circuit (PDC) is investigated as a linearization technique for the purpose of suppressing non-linear distortions, especially the third order intermodulation distortion (IMD3) and the fifth order intermodulation distortion (IMD5) simultaneously. An analog pre-distortion circuit (PDC) is designed and fabricated based on the transmission characteristics of a modulator integrated distributed feed-back (DFB) laser (EML). The PDC is low cost, compact and has broad operational bandwidth. It is designed to operate in the bandwidth up to 6 GHz, using two beam-lead silicone Schottky diodes as predistorter. The linearization by this PDC is verified in EML modulated RoF transmission system. First, by using the EML modulated RoF, Spurious Free Dynamic Range (SFDR) improvement of over 11 dB is achieved related to IMD3 and over 3 dB related to IMD5 for the entire bandwidth. Similarly, the SFDR improved by more than 6 dB related to IMD3 and by more than 4 dB related to IMD5 for another EAM modulated RoF throughout the entire bandwidth. When Wi-Fi signals at 2.4 GHz and 5 GHz were transmitted through the EML modulated RoF, error vector magnitude (EVM) was improved by 1.3 dB at 2.4 GHz and by 1.55 dB at 5 GHz for back-to-back (BTB) transmission. For 10 km single mode fiber (SMF) transmission, EVM improved by 1.07 dB at 2.4 GHz and by 1.03 dB at 5 GHz. For the EAM modulated RoF, EVM was improved by 2.76 dB at 2.4 GHz and by 1.45 dB at 5 GHz for BTB transmission. For 10 km SMF transmission, EVM was improved by 2.08 dB at 2.4 GHz and by 1.44 dB at 5 GHz. Moreover, Wi-Fi signals were generated at a RF carrier of 2-5 GHz and EVM improvements were recorded. For the EML modulated RoF, EVM improvement was more than 1.4 dB for BTB transmission and more than 1 dB for 10 km SMF transmission. For the EAM modulated RoF, EVM improvement was more than 1.4 dB for both BTB and 10 km SMF transmission.


identifier: Jackson, Renee Elizabeth  (2016) Towards Affinity Spaces in Schools: Supporting Video Game-Design Partnerships as Twenty-First Century Learning Tools.  PhD thesis, Concordia University.

abstract:
Abstract
Towards affinity spaces in schools: Supporting video game-design partnerships as twenty-first
century learning tools
Renee E. Jackson, Ph.D.
Concordia University, 2016

The Arcade Our Way (AoW) project was an intergenerational, all female, video game design based project involving fifteen grade seven students, five undergraduate students, the CEO of a small gaming company and the researcher who both participated and observed. This ethnographic pilot study was an investigation of the merits of the project as a twenty-first century learning tool, where twenty-first century learning is aligned with the views of John Dewey and Paulo Freire. The project is considered for its strength as a progressive learning space through the lens of contemporary informal online learning spaces knowns as affinity spaces (Gee, 2005), and “energizing moments” a tool developed through data analysis. Affinity spaces are nonhierarchical and constructivist in nature, and participants of all ages learn from one another based on shared interests. Specifically the fourteen features of nurturing affinity spaces (Gee & Hayes, 2012) were used as reflective tools through which to consider the strength of the project as a constructivist learning environment. Each feature was then evaluated through a five point rubric and ranked according to its relative strength. To further corroborate the merit of the project from a student centred perspective, “energizing moments” provided indicators of the moments when the participants were most highly engaged by the work. This is another approach to attending to the strength of this project, and perhaps other projects as well, based on the idea that student motivation matters. Identifying energizing moments throughout the project can not only provide further insight into the strength of the project from a student-centred perspective, but can support strategies for enabling future such motivation. These tools were used to derive recommendations towards future iterations of the project. This research comes from the perspective that twenty-first century learning strategies have much to learn about pedagogy from the ways young people are motivated within the context of specific projects, and from their informal learning choices outside
of school through technology and the internet.

Keywords: video games, gender, new-media literacy, collaboration, progressive education,
traditional education, twenty-first century learning, real-world learning, experiential learning,
partnerships.


identifier: Amini, Marzieh  (2016) Wavelet Domain Watermark Detection and Extraction using the Vector-based Hidden Markov Model.  PhD thesis, Concordia University.

abstract:
Multimedia data piracy is a growing problem in view of the ease and simplicity provided by the internet in transmitting and receiving such data. A possible solution to preclude unauthorized duplication or distribution of digital data is watermarking. Watermarking is an identifiable piece of information that provides security against multimedia piracy. This thesis is concerned with the investigation of various image watermarking schemes in the wavelet domain using the statistical properties of the wavelet coefficients. The wavelet subband coefficients of natural images have significantly non-Gaussian and heavy-tailed features that are best described by heavy-tailed distributions. Moreover the wavelet coefficients of images have strong inter-scale and inter-orientation dependencies. In view of this, the vector-based hidden Markov model is found to be best suited to characterize the wavelet coefficients. In this thesis, this model is used to develop new digital image watermarking schemes. Additive and multiplicative watermarking schemes in the wavelet domain are developed in order to provide improved detection and extraction of the watermark. Blind watermark detectors using log-likelihood ratio test, and watermark decoders using the maximum likelihood criterion to blindly extract the embedded watermark bits from the observation data are designed.
 Extensive experiments are conducted throughout this thesis using a number of databases selected from a wide variety of natural images. Simulation results are presented to demonstrate the effectiveness of the proposed image watermarking scheme and their superiority over some of the state-of-the-art techniques. It is shown that in view of the use of the hidden Markov model characterize the distributions of the wavelet coefficients of images, the proposed watermarking algorithms result in higher detection and decoding rates both before and after subjecting the watermarked image to various kinds of attacks.


title: Towards Affinity Spaces in Schools:  Supporting Video Game-Design Partnerships as Twenty-First Century Learning Tools


identifier: Wan, Min  (2016) Modifiable Areal Unit Problem (MAUP) Effects on Assessment of Accessibility via Public Transit.  Masters thesis, Concordia University.

abstract: Integrating accessibility by public transit with land use planning is a crucial precondition for sustainable urban development. Accessibility by public transit has been widely assessed in a GIS environment using aggregated zonal data, such as traffic analysis zones, census tracts, dissemination areas, dissemination blocks, 200 * 200 m grids and 50 * 50 m grids. Nevertheless, it has been proved that the scale and zoning scheme of zones may alter analysis results, which is known as the Modifiable Areal Unit Problem (MAUP). Therefore, it is essential to know how the MAUP affects assessment of accessibility. This research addressed the MAUP effects, when evaluating accessibility based on cumulative opportunity measures. This research applied a cumulative accessibility measure, which calculated accessibility in terms of the number of urban nodes that could be reached within a given travel time or distance. The City of Windsor, Canada, was used as the study area. The MAUP effects were examined based on 6 types of zones (e.g. census tracts, dissemination areas, dissemination blocks, 0.6 km, 0.3 km and 0.15 km grids) at comparable scales or zoning schemes. It was found that the MAUP may significantly alter assessment results of accessibility and should be paid highly attention to. The two outcomes of the MAUP effects on accessibility measurements are: changes of accessibility score and alterations of policy implications that are based on accessibility measurements. Three ways were discussed to deal with the MAUP impacts on accessibility measurements: using disaggregate data if possible, using low aggregated data and selecting zones according to research purposes.


identifier: Leon, Abelardo  (2016) Homomercracia. Social Change and Sexual Diversity in Times of Emerging Neoliberalism in Chile.  PhD thesis, Concordia University.

abstract:
During the last few years, increasing sensitivity has been shown toward civil and sexual rights for gay, lesbian and transgender people in Chile. There are several reasons for this, which include, for example: the emergence of the student movement in 2006, which encouraged several social groups to demand recognition of their rights, and institutional support from the conservative government of Sebastián Piñera (2010-2014). From here, important steps in favor of the LGBT population where taken, making them more visible in the media, approving the antidiscrimination law in 2012, and creating the conditions for the approval of the civil union agreement in 2015 during Michelle Bachelet’s tenure as president.
Accordingly, this qualitative case study examines the symbolic dimension of LGBT civil rights discourse in the 10 years leading up to the approval of the civil union agreement in 2015. This research uses phenomenology as a broad conceptual umbrella, and Critical Discourse Analysis and Multimodality as methodological approaches. In this sense, this study is grounded in three interdisciplinary areas: Discourse Analysis, Queer Studies and the study of Social Movements. I have analyzed this political moment as the effect of a new relationship between homosexuality, the global market and liberal democracies using a concept which I call Homomercracia. My conclusion is that under these economic and political conditions, the commodification of homosexuality leads to the emergence of a regulated pattern of homosexuality—a white, male, socially successful professional—which, though widely accepted in Chilean society, is strongly marked by racial and economic biases.

Key words: Homomercracia, Social Change, Discourse Analysis, LGBT Studies, Empathy


identifier: Rashid, Azra  (2016) Naristhan/Ladyland: Gender, Nationalism and Genocide in Bangladesh A Research-Creation Project.  PhD thesis, Concordia University.

format: text video

abstract: Naristhan/Ladyland is a research-creation project that challenges the selective remembering, silencing and appropriating of women’s experiences in the widely circulated images of the 1971 genocide in Bangladesh. As a video, the project juxtaposes the testimonies of survivors and national memory of the war and creates a shift of perspective that demands a breaking of silence. Employing research-creation as methodology, the video and written component engage with the existing feminist scholarship on gender, nationalism and genocide and the archive of the Liberation War Museum in Bangladesh to investigate the dominant representations of gender in the 1971 genocide in Bangladesh. The archive of the war museum in Bangladesh is viewed as a site of institutionalized dialogue between the 1971 genocide and the national memory of that event. An examination of the archive allows us an opening point into the ideologies that have sanctioned a particular authoring of history, which is written from a patriarchal perspective. The photographs on display at the Liberation War Museum offer a crystallizing moment in the national memory; they invoke the resilience and survival of the nation in a war that was largely fought by the men of the country on behalf of the nation. It omits the victimization of women, which did not end with the war in 1971. To question the archive is to question the authority and power that is inscribed in the archive itself and that is the function performed by testimonies in this research. Testimonies are offered from four unique vantage points – rape survivor, freedom fighter, religious and ethnic minorities – to question the appropriation and omission of women’s stories. Furthermore, the emphasis on the multiplicity of women’s experiences in war seeks to highlight the counter-narrative that is created by acknowledging the differences in women’s experiences in war instead of transcending those differences.


identifier: Kaul, Mrinal  (2016) Abhinavagupta’s Theory of Reflection A Study, Critical Edition and Translation of the Pratibimbavāda (verses 1-65) in Chapter III of the Tantrāloka with the commentary of Jayaratha.  PhD thesis, Concordia University.

abstract:
The present thesis studies the theory of reflection (pratibimbavāda) as discussed by Abhinavagupta (fl.c. 975-1025 CE), the non-dualist Trika Śaiva thinker of Kashmir, primarily focusing on what is often referred to as his magnum opus: the Tantrāloka. The present study has as its foundation a new critical edition of a small, nonetheless important, passage of the Tantrāloka—chapter-3, verses 1-65 and the commentary titled -viveka thereon by Jayaratha (fl.c. 1225-1275 CE)—along with an annotated English translation. The edition here presented represents the very first philologically exhaustive edition of any part of the Tantrāloka or Tantrāloka-viveka.
	The textual critical exercise undertaken in this thesis based on the examination of twenty-nine manuscripts has shown that the textual transmission of the Tantrāloka and -viveka (at least of the small part that I have studied) thereon has undergone corruption, but of a minor sort. The present edition is a much improved version over the editio princeps yet nothing significantly different from the latter as far as the interpretation of the text is concerned.
	Abhinavagupta’s teachings are laid deep under the esoteric influence of the Kaula and the Krama systems, and he employs a robust model of developing a critical dialectical structure that manifests in his works like those of the theories of reflection amongst many others. In the Tantrāloka as also in his other Trika works, he is endeavouring to establish a unique ontological status to a reflected object (pratibimba) rejecting the thesis of Naiyāyikas, Sāṃkhyavādins and Vijñānavādins. The varied textures of his hermeneutics finds groundings in many branches of knowledge as diverse as metaphysics, epistemology, soteriology, aesthetics, mysticism  and phenomenology.


identifier: Ioannidis, Zissis  (2016) Double Skin Facades Integrating Photovoltaic Panels, Motorized Shades and Controlled Air Flow.  Masters thesis, Concordia University.

abstract:
A Double Skin Façade (DSF) with photovoltaic panels and automated roller shading devices aims at the reduction of the energy consumption of the building and at the on-site generation of electricity while allowing for the possibility of admitting ventilation air from outside without the direct noise and wind-induced direct inflow from open windows.
A detailed transient finite difference model has been developed aiming at analyzing the thermal and electrical performance of an innovative DSF integrating photovoltaics and roller blinds (DSF-P). The model takes into account the effects of wind and the daylight provisions to the adjacent zone of the DSF-P. The energy balance of the system is described by a thermal network and a nodal flow network capable of assessing the wind effects on the cavity along with a daylighting model. In the modeling of the DSF-P the thermal behavior of an adjacent perimeter zone as well as the shading that the photovoltaics and the roller blind provide to the interior skin of the building are also simulated.
The model developed was used for the numerical investigation of various flow rates and shading configurations for a south facing three-storey double skin façade considering a typical year in Montreal (Canada). Different flow rates inside the cavity and shading configurations were considered and simulated. It was concluded that the optimal cavity width, in which the electricity consumption of the DSF-P system is minimized is between 0.2m and 0.6m (0.07 and 0.21 L/H); the electricity generated from the photovoltaics integrated on the exterior skin may cover the total electricity consumption of the adjacent zone; and for some cases an energy positive DSF-P can be generated.


identifier: McMaster, Scott R.  (2016) Crowdsourcing Global Culture: Visual Representation in the Age of Information.  PhD thesis, Concordia University.

abstract: This doctoral dissertation extends existing frameworks of visual content analysis by coupling them with crowdsourcing technologies for international data collection and an iterative, interpretative visual analysis. In the age of information, imagery continues to be consumed and circulated at exponential rates, influencing and changing global flows of information that parallels Internet communication technology as it penetrates and gains ubiquity in new regions. To investigate the visual, media, and cultural phenomena that lie within these globalized pictorial exchanges, a flexible, visually-based inquiry is essential. This qualitative, visual-ethnographic survey was conducted over the Internet and aims to help inform visually-based literacy and media studies and further image-based research methodologies. The researcher collected over 2000 drawings from 61 countries diverse in geography and culture. The researcher revealed fresh insights into the visual-textual relationship, identity, and representation in a globalized context, specifically looking at emergent tensions between local and global ways of interpretation and meaning construction online.  The researcher also considers the effects of a technologically mediated visual culture and its potential to influence or change deeply ingrained ideas once specific to geography and culture into new global trends and evolving material practices. The analysis is centred on a selection of drawings from 106 Asian participants who drew intercultural representations of the words meal, marriage, and home. The most striking discoveries indicate varying degrees of homogeneity and hybridity among the visual cultural representations received and reveals connections among language, the Internet, advertising, and identity. The findings break with more traditional views of globalization occurring in a direct West-East flow and highlight regional powers that can serve as cultural hubs of attention. These hubs act as filters, possibly creating and hybridizing new commercial and cultural trends and positioning themselves as beacons of modernity with considerable visual cultural influence.   The researcher also makes suggestions for future studies using an extended multimedia visual methodology as well as the potential inherent in emerging technologies for exploring phenomena in artistic, educative, and academic contexts.


identifier: Shamseldin, Shokry Ibrahim  (2016) Analysis and design of microwave devices based on ridge gap waveguide technology.  PhD thesis, Concordia University.

abstract: The usage of high frequency microwave devices is rapidly increasing with the advances achieved in the communication systems. However, the standard guiding structures have high losses such as microstrip technology, or difficulty in manufacturing such as in the case of waveguides.   The newly developed ridge gap waveguide (RGW) technology resolves the problems above as it has low losses and does not require electrical contacts as required in the waveguides.  The concept of RGW is simple as it allows the wave propagations in the guiding part and eliminates the leakage in all other directions. The region that surrounds the ridge consists of two parallel surfaces; one is a perfect electric conductor (PEC) and the second is a perfect magnetic conductor (PMC). The gap between the two surfaces should be less than a quarter wavelength.  Periodic conducting nails realize the PMC that practically has a possible bandwidth 2.5:1 and in some cases exceeds 3:1. Usually, the design of these surfaces relies on the unit cell analysis that is based on determining its band gap, the estimation of the band gap is performed numerically. The band gap of the cell is the operating bandwidth of the complete structure. For the first time, we presented a method to measure the band gap from s-parameter measurements. Utilization of the broadband characteristics strongly depends on the proper design of the transition between the RGW and the standard guiding structures and connectors. Most of the available transitions make use of around one-third of the possible bandwidth. Therefore, we present new transitions that utilize the whole possible bandwidth of the RGW. The presented work can be divided into four major parts. Several microwave components are designed based on the RGW such as power divider, hybrid couplers, and a circulator. New methods are presented for efficient and accurate design of these components. One of the main contributions is related to the RGW circulator design; it's an accurate design procedure that can be used with other technologies as well. In addition, a new setup to measure the low relative permittivity of thin materials such as fabrics is presented. An example of a leaky wave antenna using split slot arrays is presented. These studies highlight the RGW advantages and can be considered as a step towards the standardization of this technology.


identifier: Leonhart, Mark W.  (2016) Responsibility and Reassurance Seeking: An Experimental Investigation.  Masters thesis, Concordia University.

abstract: Excessive-reassurance-seeking (RS), conceptualized as a form of compulsive checking in obsessive-compulsive disorder (OCD), is distressing both for the seeker and for their loved ones.  Experimentally increased responsibility leads to more checking symptoms and greater urges to seek reassurance.  We hypothesized that under conditions of high responsibility (HR), participants would seek more reassurance than those in a low responsibility (LR) condition.  Seventy-eight undergraduate participants were randomized to either HR or LR, completed a novel dishwashing task with a confederate, and were then given an opportunity to seek reassurance following ambiguous feedback.  The number of instances of RS was reported by participants, confederates, and later coded by trained volunteers who were blind to the study’s hypotheses and listened to recordings of RS conversations.  HR participants reported greater urges to seek reassurance t(76) = -2.891, p = .005, d = 1.23; sought more reassurance, both according to confederates, F(1, 76) = 10.741, p = .002, ηp2 = .124 and coders, F(1, 76) = 6.872, p = .011, ηp2 = .083; but self-reported RS did not differ between conditions, F(1, 76) = 1.480, p = .228, ηp2 = .019.  Objective coding revealed that LR and HR participants did not differ on overt RS, F(1, 76) = 1.258, p = .266, ηp2 = .016; however, HR participants sought more covert reassurance, F(1, 76) = 18.079, p < .001, ηp2  = .192.  Participant-reported responsibility decreased following RS, t(47) = 2.457, p = .018, d = .35, suggesting RS may function not only to reduce anxiety but also to transfer responsibility away from the seeker.  Implications for cognitive models of and treatments for RS in OCD are discussed.


identifier: Babaee, Fatemeh Yassaman  (2016) Removal of Arsenic from Water and Immobilization in Soil Using Iron/Copper Nanoparticles.  PhD thesis, Concordia University.

abstract: In this research, iron/copper bimetallic nanoparticles were used to remove arsenic from aqueous solutions as well as its immobilization in soil matrix. Nanoparticles were synthesized using two different protocols, resulting in two different sizes of particles and the physicochemical characterization was determined using XRD, TEM, BET and XPS techniques. To apply the nanoparticles in a soil environment, nanoparticles were stabilized with various starch concentrations. Characterization of nanoparticles resulting from the two methods of synthesis indicated that the mean diameter of nanoparticles were 13.17 nm and 27.15 nm. For both nanoparticles, adsorption isotherms fit well with the Langmuir equation and the maximum sorption capacities for As(III) and As(V) were 19.68 mg/g, and 21.32 mg/g respectively at pH 7.0 for the first nanoparticle size and 5.55 mg/g and 10.41 mg/g for As(III) and As(V) respectively for the second nanoparticle size. The kinetic test revealed that sorption follows pseudo-second-order and coexisting HCO3-, SO42- , and PO43- had an insignificant influence on arsenic adsorption at  equal initial concentrations to As. Based on transport studies, for immobilization of arsenic in contaminated soil, 0.04 wt.% starch stabilized Fe/Cu nanoparticles were used. For this nanoparticle, the Langmuir adsorption isotherm was fitted and showed the maximum sorption capacity of 90.1 mg/g, and 126.58 mg/g for As(III) and As(V) respectively. Soil column breakthrough tests and elution profiles proved the mobility of the starch stabilized nanoparticles when 15% of the nanoparticles were retained in the soil bed. Starch stabilized Fe/Cu nanoparticles were highly effective for arsenic immobilizing in the contaminated soil. When the soil was treated in batch experiments with nanoparticles (0.4 g/L) at a soil to liquid ratio of 0.1, the water leachable arsenic was reduced from 55 µg/L to 4.23 µg/L. Column elution tests indicated that application of a starch stabilized Fe/Cu suspension transferred nearly all water-soluble arsenic to nanoparticle phase. Then arsenic can become immobilized in the soil bed as the nanoparticles are immobilized in the soil matrix. The results of this research can lead to introducing an effective and efficient alternative adsorbent for removal of arsenic from water and its stabilization in contaminated soils.


identifier: Mugabo, Délice Igicari  (2016) Geographies and Futurities of Being: Radical Black Activism in a Context of Anti-Black Islamophobia in 1990s Montreal.  Masters thesis, Concordia University.

abstract: This thesis analyzes the connecting political, spatial, and spiritual aims of Black activists in 1990s Montreal. I investigate how they worked at reconfiguring the Black community in Montreal against the East/West language divide. I also examine how the White anti-racist Left developed anti- Black Islamophobic discourses against radical Black activists who were Muslim and/or associated with Islam. Lastly, I pay particular attention to the role of spirituality in the visions that radical Black activists had for the Black community in Montreal. This research offers us a way to understand how Black geographies emerge and how they exceed geographies of domination. It seeks to contribute to a body of literature in Black geography through an investigation of how Black radical organizing reimagines and transforms space and place.


identifier: Goldner, Jonathan  (2016) Teaching the Whole Body: Apprenticeships in Gwich'in Canoe Building.  Masters thesis, Concordia University.

abstract: Academic inquiry has long privileged abstract knowledge by creating cognitive schemas of understanding that are primarily transmitted through language. Given that we understand the world through all of our sensory modes and bodily participation, apprenticeships offer a unique opportunity to study the multiple ways in which we acquire knowledge. This thesis considers how embodied knowledge is co-constructed between master and apprentice in the context of a long-term research creation field study with skilled craftsmen learning to build birch bark canoes. In repudiating the separation of mind and body, and the categorical tidiness of dialectical models that address the interactions between people, objects and the environment, it is herein argued that knowledge emerges in a field of total corporal experience that is embodied through skilled practices. Apprenticeships in canoe building reveal that while dialogue is an important instructional tool, kinaesthetic interactions with materials situated in landscapes are also profound actors in ways of knowing.


identifier: Pourhosseini, Omid  (2016) Availability based maintenance scheduling in Domestic Hot water of HVAC system.  Masters thesis, Concordia University.

abstract: Reliability centered maintenance is an analytical tool for preventive maintenance planning. The availability based maintenance method is a branch of reliability centered maintenance, which considers mean time to failure (MTTF) and mean time to repair (MTTR). MTTF of a system is identified from the reliability distribution of its components, and MTTR defines maintenance period of components. In this sense, a reliability function is determined from historic failure data of components during their operation period (in form of a bathtub curve). MTTF is calculated based on this reliability function. This thesis is based on availability based maintenance on the domestic hot water (DHW) of HVAC system, which incorporates the time needed for maintenance of components in availability analysis. The Keeping system availability (KSA) method provides maintenance scheduling by considering the outcomes of the maintenance on the DHW system, while maintaining the availability of the current system. This method has been developed in the maintenance scheduling of power plants as the continual availability of the power generation systems is a critical issue. We have adopted this approach for DHW system of HVAC, which is a critical component in provision of hot water during long cold seasons in Canada. The availability based maintenance approach with KSA decision process has been developed to optimize the maintenance schedule of components in order to prevent over-maintenance. For this purpose, we rely on MTTF and MTTR. MTTF is quantified by the reliability function in a component, and its value should be modified based on pre-defined scenarios, which indicate average maintenance interval (AMI) types. Then, the existing components with a different maintenance times are sorted according to the maintenance effect on keeping the availability of the system, while reducing the maintenance cost. The sorting list is divided into two groups: top loop (components with low maintenance effect), and bottom loop (components with high maintenance effect). After running the KSA decision process, the outcomes consist of different “STEP NO” with different combinations of maintenance scenarios in the existing components in the DHW system. The main criterion in selection of the “STEP NO” is to have the modified availability (system with maintenance plan) equal to or greater than the current system availability (system without maintenance plan). In the next step, we examine changing the arrangement of the heat transfer sub-system from parallel to standby in order to reduce maintenance cost, while keeping the availability of the system at the same level. In addition, a replacement analysis is performed on the heat exchanger to identify the replacement time in its repairable subcomponents. Finally, a life cycle cost (LCC) analysis is performed to compare the maintenance cost and replacement cost between these two options.


identifier: Kinner, Adam  (2016) Suite canadienne (2015): Re-Performance & Otherwise Movements.  Masters thesis, Concordia University.

abstract: This thesis examines a work of video documentation made by the author called Suite canadienne (2015). The video documents a series of re-performances of a ballet titled Suite canadienne made in 1957 by Ludmilla Chiriaeff, the founder of Les Grands Ballets Canadiens de Montréal and the first major, government-supported choreographer in Québec. Part 1 of the thesis situates the original 1957 work in the political, cultural and social context from which it emerged. It shows how the original work positioned itself as an originary work of Québec dance and manifested a “hailing” of the subject, following Louis Althusser’s theory of interpellation. The author theorizes this hailing as a mobilization of subjective arrest that posits sovereignty as arrestation-in-movement. Part 2 discusses the technique of re-performance in relation to the political, historical and nomological power of the archive. In this way, the author argues for the uses of re-performance as so many strategies for refusing the proliferation of normative culture within and through the dancing body. The thesis examines the 2015 re-performances through three of their aspects: (1) the undisciplining of the ballet body, (2) the reterritorialization of administrative architectures and (3) the performance of experimental subjectivities. The final section, the “coda,” relates all of these aspects to the notion of “otherwise movements” that perform the normative while simultaneously recasting it, allowing for real deterritorializations and lines of flight.


identifier: Walker, Cody  (2016) Keys Type Mouse.  Masters thesis, Concordia University.

title: Keys Type Mouse

format: text archive text

abstract:
This is a work digital storytelling. Each piece explores a different affordance of digital text.
"Mouse" uses the screen's plane as the ground for its exploration: the reader's cursor reveals, snips and
exposes the malleability of digital text. "Keys" invites the reader to perform its inscription by typing: to
advance the text, the reader must use the keyboard. "Type" takes this to an experimental extreme: it
provides a playground for letterforms to interact and collide. The text is created and altered by each
character the reader inserts.


identifier: Horen Greenford, Daniel Stephen ORCID: https://orcid.org/0000-0002-8390-9388 <https://orcid.org/0000-0002-8390-9388>  (2016) The equitable allocation of greenhouse gases.  Masters thesis, Concordia University.

abstract: National Emissions Inventories (NEI) use Production-Based Accounting (PBA), which include only emissions generated within a nation's territory. Thus, there are presently no considerations of indirect emissions linked to imported products in national accounts of greenhouse gas emissions. International trade has undermined climate policy to date — as much as 30% of global emissions are linked to production for export and are therefore not subject to mitigation policy. Furthermore, conventions are often mistakenly conflated with responsibility for climate change. This research proposes a weighting metric rooted in normative ethics to allocate Emissions Embodied in Trade (EET) between trading partners — Equity Weighted-Based Accounting (EWBA). Additionally, this study quantifies subsistence and luxury emissions. The metric is constructed to weigh EET inversely to how vital a given trade is for each country taking part. Need to engage in trade is quantified using use-value for money and products exchanged in a given trade, derived from the relation between human welfare and income and its mapping onto products purchased. New NEIs are then computed and compared with those by PBA and CBA. It is found that EWBA emissions suggest higher abatement responsibility than PBA emissions for most affluent countries, though usually less than if EET were divided equally between producers and consumers. EWBA provides a policy-ready alternative to PBA that is arguably fairer than CBA. If adopted as the convention in international climate policy, NEIs computed using EWBA would better reflect responsibility for climate change and emissions abatement, yielding more equitable and effective climate policy.


identifier: El Khoury, Nicolas  (2016) Placement and Scheduling of Network Traffic on Virtual Network Functions.  Masters thesis, Concordia University.

abstract: Hardware MiddleBoxes represent a vital part in today's networks. Despite their important roles, they are accompanied by several problems, namely, their lack of flexibility, high capital and operational expenditures, and power consumption. Network Function Virtualization is one promising solution to address these problems. This trend replaces the MiddleBoxes by software-based entities. Indeed, these Virtual Network Functions promise to alleviate the numerous disadvantages brought by their hardware counterparts. One of these most serious issues is the steadily increasing power consumption. Studies suggest that the Virtual Network Functions will reduce the electricity costs needed to turn on and operate the hardware functions. In order to further optimize the power consumption of the network, an efficient framework, capable of placing and scheduling traffic on these VNFs, is needed. Such a framework allows to optimally map and schedule the flows to be serviced, and place the unused servers in energy saving modes. In this thesis, we assume VNFs are already placed on physical machines. We consider traffic flows with deadlines. We aim at assigning and scheduling flows to VNFs in the most energy efficient manner. We formulate this problem mathematically and, owing to its complexity, present an efficient algorithmic method for solving the problem. We compare our heuristic with two other approaches, one of which aims to minimize the makespan, and the other to minimize number of servers used. We show that our heuristic combines the advantages of both approaches and generates better results by consuming up to 31.3% and 46.1% energy less than other two approaches respectively. Further, we extend the existing work in the literature, and solve the problem of placement of traffic flows on VNFs while taking into account the transmission delay between pairs of VNFs, and the routing of the virtual links on the underlying physical network.


identifier: Ebrahimi Khonacha, Samira  (2016) Numerical Modeling of Foundations on Dense Sand Overlaying Loose Sand.  Masters thesis, Concordia University.

abstract:
Foundation built on layered soil is often encountered in the field. Layered-soil profile could
be either a natural or artificial phenomenon. For structures with large footing dimensions two
layers of subsoil are usually involved in the determination of bearing capacity of soil. Also,
building of heavy structures on weak soils often needs a blanket of granular material to cover the
natural soil and increase the soil bearing capacity. In fact, the granular layer both distributes and
alleviates the load pressure due to the infrastructure. Popular weighted average method and
projected area method fail to predict accurately the soil bearing capacity when the upper layer is
dense sand.
This thesis investigates the bearing capacity of strip footings on a layer of dense sand
underlined by loose sand. The effects of thickness and shear strength of top layer as well as the
embedment depth of footing were investigated. A numerical model was developed to predict the
bearing capacity of footing on layered sand. The results showed that the bearing capacity of strip
footings on dense sand (with friction angle, φ, higher than 40 degrees) with and without
embedment depth is overestimated by weighted average method and is underestimated by
projected area method. Comparison with the available theory and experimental result are
presented. It is of interest to report herein that, in the absence of surcharge the footing bearing
capacity from numerical analysis was always less than Hanna (1981). In the presence of the
surcharge load due to the embedment depth of footing, the results were close to that obtained by
Hanna (1981).


identifier: Abulkhair, Hani  (2016) Experimental Investigation of the Flow Dynamics in a Model of an Abdominal Aortic Aneurysm.  PhD thesis, Concordia University.

abstract:
An Abdominal Aortic Aneurysm (AAA) is a vascular disease affecting seniors. It is described by an inflation of the aorta in the abdominal regions. The specific reason for this disease is not clear.Rupture of AAAs leads to death and current surgical interventions are risky and require frequent follow-up AAAs are usually associated with an Intraluminal Thrombus, which prevents blood from conveying oxygen and nutrition to the AAA walls. Formation of thrombosis are strongly affected by hemodynamics, and especially blood stasis.

It has been founded that blood stasis can be triggered by a reduction of flow rate such as that during sleeping or in people who suffer from lower limb amputation.

This change has been evaluated experimentally by time-resolved Particle Image Velocimetry. A compliant AAA model that has an aortic arch, renal arterirs, and an iliac bifurcation was designed
and tested under normal and low flow conditions in terms of velocity behavior, residence time of particles inside the AAA, and shear history of particles during their movement.

Proper orthogonal decomposition and Dynamic mode decomposition have been applied to the flow in both planes to reveal the hidden dynamics and the coherent structures of the flow behavior inside the AAA.

The flow inside an AAA is mainly described by the jet penetrating the AAA with a large recirculation zone in the lumen. The velocity snapshots do not show a major difference between the two cases. Hidden dynamical structures were revealed by proper orthogonal decomposition and dynamic mode decomposition. Most of the small-scale dynamics occur near the entrance of the AAA. Vortical structures have been found to play a beneficial role in preventing thrombus formation. This study recommends focusing on the low flow conditions and developing a method that can promote blood flow mixing in patients with an AAA. The current study is the first study to evaluate the time-resolved behavior of the fluid flow inside AAAs and to decompose it into dynamical modes.


identifier: Li, Jing  (2016) Full Solution Indexing and Efficient Compressed Graph Representation for Web Service Composition.  PhD thesis, Concordia University.

abstract:
Service-oriented computing enhances business scalability and flexibility; providers who expect to benefit from it may bring explosive growth of web services. Searching an optimal composition solution with both functional and non-functional requirements is a computationally demanding problem: the time and space requirements may be infeasible due to the high number of available services. In this thesis, we study QoS-aware service composition problems which satisfy functional requirements as well as non-functional requirements. We use optimization algorithms to enhance accuracy of our searching algorithms.

In the first approach, we propose a database-based approach to search a service composition solution. Current in-memory methods are limited by expensive and volatile physical memory, to deal with this problem, we want to use the large space available in relational database on persistence disk. In our database-based approach, all possible service combinations are generated beforehand and stored in a relational database. When a user request comes, SQL queries are composed to search in the database and K best solutions are returned. We test the performance of the proposed approach with a service challenge data set; experiment results demonstrate that this approach can always successfully find top-K valid solutions.We offer three main contributions in this approach. First, we overcome the disadvantages of in-memory composition algorithms, such as volatile and expensive, and provide a solution suitable to cloud environments. Second, we fetch top-K solutions in case the optimal solution is not available as backup solutions to the user. Third, compared with other pre-computing composition methods, we use a single SQL query: there is no need to eliminate spurious services iteratively.

Then, we propose the application of a skyline operator to reduce the search space and improve the scalability. Skyline analysis returns all of the elements that are not dominated by another element. We use skyline analysis to find a set of candidate services referred to as "skyline services", therefore, less competitive services are reduced. This allows us to find a solution for a large composition problem with less storage and increased speed.

In reality, different users may have same requests, we are motivated to pick some popular requests and generate paths for fast delivery. These paths are stored in a separate table of the relational database. When a user request comes, we first search to find a nearly ready-made solution. Only as a last resort do we search the table with whole paths to find a solution.

Finally, to deal with the problem that the search space may explore, we apply a compressed data structure to represent the service composition graph. The goal is to allow algorithms running in in-memory over larger graphs. In this approach, we use compact K2-trees to represent the service composition graph. When a user request comes, we search the K2-tree for a satisfactory solution. We use an array to store values in the last level of the compact tree, which represents relationships between services and concepts. In our algorithms, we find services' inputs (resp. outputs) by locating elements in this array directly, therefore, decompressing the graph is unnecessary. To the best of our knowledge, our work is the first attempt to consider compact structure in solving web service composition problems. Experiment results demonstrate that this approach takes less space and has good scalability when handling a large number of web services.

We provide different approaches to search a solution for the user. If the user want to find an optimal solution with fewer services, he may use the database-based approach to search for a solution. If the user want to get a solution in a short time, he may choose the in-memory approach.


identifier: Elsafty, Nehad  (2015) Automatic Hardhat Wearing Detection to Enhance Construction Site Safety.  Masters thesis, Concordia University.

abstract:
ABSTRACT
Automatic Hardhat Wearing Detection to Enhance Construction Site Safety
Nehad Elsafty
Careers in the construction field are involved with risks and engender a wide range of dangers to which workers and professionals are exposed on a daily basis. Numerous injuries and deaths are reported annually. Injuries and deaths have multiple negative financial, emotional, and psychological consequences on the affected persons and their families. In addition, these accidents increase the time and costs of construction projects. Therefore, construction site safety is a critical issue that needs to be monitored and controlled throughout the construction project timeline by both professionals and contractors. Hardhat wearing is one of the basic safety regulations at construction sites, to which all workers and visitors should adhere all of the time. This study proposes a new automated method to determine if workers and others present on construction sites are wearing hardhats (or not). This method could automatically create alarms for those workers who are not wearing hardhats. The method comprises the following steps. First, video frames captured by fixed cameras on the construction site are used for the detection of human bodies and hardhats. Next, the detected human bodies and hardhats are matched using their geometric and spatial relationships. Those human bodies without their matched hardhats are highlighted to bring them to the attention of the onsite safety inspectors. This method has been tested using real site videos. The safety alert’s precision and recall demonstrates its effectiveness and potential to enhance onsite safety monitoring.


identifier: Zhang, Suiqing  (2016) Institutional Logics and Organizational Strategies: Case Studies of Five Bike-sharing Operators in China.  Masters thesis, Concordia University.

abstract:
This exploratory study investigates how managers of five China’s bike-sharing program (PBS) operators understand the mission(s) of their organizations, how they perceive legitimacy, and how they seek to overcome organization challenges. More specifically, the study focus on two research questions: (1) How do PBS operation organizations understand themselves? (2) What are PBS’ organizational strategies towards multiple demands? Recently, the public and academia have raised concerns about PBS programs’ impact (Waldmeir, 2014; Alcoba, 2012). PBS operators also report operation challenge such as legitimacy issues and business model sustainability. The study adopts the “institutional logics perspective” (Thornton, Ocasio & Lounsbury, 2012) and analyzes the institutional logics suggested from several organizational aspects to understand PBS’s organizational nature and strategy. It also compares the differences among the five organizations. The results offer a detailed description of the institutional logics of these operators, as well as some suggestions on PBS management and future institutional studies.
This study helped encourage actors from different areas of the society understand the PBS organizations’ nature and strategy, as well as to encourage more studies on hybrid organizations that face conflicting logics and make public projects more sustainable and beneficial to the general public.


identifier: Monette, Alexander  (2016) Terminologie anglais-français du droit des affaires canadien.  Masters thesis, Concordia University.

abstract: Le droit des affaires canadien se caractérise par la coexistence de deux systèmes juridiques, le droit civil et la common law, au sein d’un seul État souverain. Une telle situation a des conséquences importantes sur le plan de la terminologie. Afin d'observer les phénomènes soulevés par cet état de choses, la présente étude a pour objectif principal de décrire les termes en usage en droit des affaires canadien en créant un fichier terminologique bilingue anglais-français de 80 fiches. Elle a également comme objectif secondaire de montrer les interactions entre les deux systèmes juridiques sur le plan terminologique et de souligner que la terminologie du droit des affaires est un polysystème interdisciplinaire parce qu’elle a de nombreux termes en commun avec la finance et la comptabilité.


identifier: Ali, Abdelmohsen  (2016) CELLULAR-ENABLED MACHINE TYPE COMMUNICATIONS: RECENT TECHNOLOGIES AND COGNITIVE RADIO APPROACHES.  PhD thesis, Concordia University.

abstract:
The scarcity of bandwidth has always been the main obstacle for providing reliable high data-rate wireless links, which are in great demand to accommodate nowadays and immediate future wireless applications. In addition, recent reports have showed inefficient usage and under-utilization of the available bandwidth. Cognitive radio (CR) has recently emerged as a promising solution to enhance the spectrum utilization, where it offers the ability for unlicensed users to access  the licensed spectrum opportunistically. By allowing opportunistic spectrum access which is the main concept for the interweave network model, the overall spectrum utilization can be improved. This requires cognitive radio networks (CRNs) to consider the spectrum sensing and monitoring as an essential enabling process for the interweave network model.

Machine-to-machine (M2M) communication, which is the basic enabler for the Internet-of-Things (IoT), has emerged to be a key element in future networks. Machines are expected to communicate with each other exchanging information and data without human intervention. The ultimate objective of M2M communications is to construct comprehensive connections among all machines distributed over an extensive coverage area. Due to the radical change in the number of users, the network has to carefully utilize the available resources in order to maintain reasonable quality-of-service (QoS). Generally, one of the most important resources in wireless communications is the frequency spectrum. To utilize the frequency spectrum in IoT environment, it can be argued that cognitive radio concept is a possible solution from the cost and performance perspectives. Thus, supporting numerous number of machines is possible by employing dual-mode base stations which can apply cognitive radio concept in addition to the legacy licensed frequency assignment.

In this thesis, a detailed review of the state of the art related to the application of spectrum sensing in CR communications is considered. We present the latest advances related to the implementation of the legacy spectrum sensing approaches. We also address the implementation challenges for cognitive radios in the direction of spectrum sensing and monitoring. We propose a novel algorithm to solve the reduced throughput issue due to the scheduled spectrum sensing and monitoring. Further, two new architectures are considered to significantly reduce the power consumption required by the CR to enable wideband sensing. Both systems rely on the 1-bit quantization at the receiver side. The system performance is analytically investigated and simulated. Also, complexity and power consumption are investigated and studied.

Furthermore, we address the challenges that are expected from the next generation M2M network as an integral part of the future IoT. This mainly includes the design of low-power low-cost machine with reduced bandwidth. The trade-off between cost, feasibility, and performance are also discussed. Because of the relaxation of the frequency and spatial diversities, in addition, to enabling the extended coverage mode, initial synchronization and cell search have new challenges for cellular-enabled M2M systems. We study conventional solutions with their pros and cons including timing acquisition, cell detection, and frequency offset estimation algorithms. We provide a technique to enhance the performance in the presence of the harsh detection environment for LTE-based machines. Furthermore, we present a frequency tracking algorithm for cellular M2M systems that utilizes the new repetitive feature of the broadcast channel symbols in next generation Long Term Evolution (LTE) systems. In the direction of narrowband IoT support, we propose a cell search and initial synchronization algorithm that utilizes the new set of narrowband synchronization signals. The proposed algorithms have been simulated at very low signal to noise ratios and in different fading environments.


identifier: Richman, Jeremy  (2016) Make Your Life Your Business: An Entrepreneurial Approach to Empowering Challenged Young Adults.  Masters thesis, Concordia University.

abstract: This thesis studies the use of an experiential entrepreneurship program to help young adults who present with learning disabilities to acquire the skills, attitudes, and self-efficacy to achieve their unique potential and to function autonomously and productively as members of their community.  The overarching theme and objectives of the pilot program are making the acquisition of life skills more interesting, engaging, and interactive, and ultimately, more effective in empowering these young adults as they navigate through their lives and able dominated society.


identifier: Tabarah, Samia  (2016) Uncertainty Communication and Consideration in EA Practice: Lessons from a Mega Transportation Project in Canada.  Masters thesis, Concordia University.

abstract:
Environmental Assessment (EA) is a tool that informs decision making of the potential adverse impacts of proposed development projects. Since EAs deal with future events, uncertainties are unavoidable. It has been found that there are different types and sources of uncertainties in EA and decision making, however; uncertainties are not always being communicated or considered. It is understood that there is a need for more explicit disclosure of uncertainties, yet there is no consensus regarding how uncertainties are perceived, communicated, and considered by those involved in, or affected by, EA, and much less is known about the contextual dynamics of uncertainty disclosure and consideration. This study attempts to better understand the relationship between context and uncertainty practice by exploring uncertainties in a Canadian transport mega project EA, the 407 East Extension in southern Ontario.
Transport mega projects are driven by a number of contextual factors, are characterized by high uncertainty, are spatially situated, inherently displacing, and highly visible. This study investigated how elements of the context hindered, supported, or influenced the way uncertainty was communicated and considered by those involved in the EA. In particular, twenty-two (22) semi-structured interviews were performed with key project informants such as project proponents, practitioners, regulators, First Nation representatives, and affected interests. Results demonstrate that uncertainties in the EA are the result of both process and context. In the process, uncertainties were significant in the preliminary and detailed assessment stages. Elements of the environmental and socio-political context were found to contribute to uncertainty as well. In particular, results indicate that location, lack of baseline data, perception, and broader politics, organizational, and regulatory factors worked to influence the way uncertainties were either communicated or considered during the EA. In our study, information about uncertainty was not disclosed in the EA. Uncertainties were minimized or strategically avoided. In order to address these limitations and better inform decision making in EA, we offer a number of recommendations. These are: the development of an uncertainty typology; guidance for uncertainty reporting; stakeholder identification and transparency in trade-offs; uncertainty management commitments; and, more attention on the context within which EA is embedded within and attempting to interact with.


identifier: Zeng, Rui  (2016) Large Eddy Simulation of Boundary Shear Stress in Water Channels of Rectangular and Trapezoidal Shapes.  Masters thesis, Concordia University.

abstract:
The flow of water in an open channel is typically turbulent, exerting shear stresses on its boundaries, i.e. the channel-bed and sidewalls. Knowledge of boundary shear stress (BSS) distributed at a channel section has many important applications. For example, the BSS distributions affect channel stability, fish habitats, and the resuspension and subsequent transport of bed sediments. However, knowledge of the BSS is far from being complete, partly because there are technical difficulties in measuring shear stresses distributed across the bed width and sidewalls. This research thesis aims to investigate BSS distributions by means of large eddy simulation (LES). This numerical technique is superior to the commonly used traditional computational fluid dynamics approaches, with respect to detailed predictions of near-boundary flow.

Water channels of rectangular and trapezoidal shapes under open-water as well as ice-covered conditions were included as LES domains in this study. The LES results of BSS from this study were compared with available data from laboratory experiments. The comparisons show that the LES results capture typical features, as reported in the literature, of BSS distributions at rectangular and trapezoidal channel sections, including the occurrence of inflection points caused by bottom vortices. The BSS is shown to vary across the bed width and sidewalls of the channel sections. The bed shear stress is relatively high in the large central portion of the bed width and drops rapidly toward the lower corners of the channel sections. The sidewall shear stress has a similar shape as the bed shear stress. The normalised bed shear stresses in the corner regions have different distributions between the trapezoidal channel and the rectangular channel section. Secondary flow in the channels are shown to cause BSS spatial fluctuations in the central portion of the channel-bed. The maximum BBS does not necessarily occur at the same location as the maximum primary velocity. As expected, the flow structures and turbulent shear stresses in the channel sections are sensitive to the presence of ice cover as well as to inflow disturbances.

The successful predictions are attributed to a proper implementation of no-slip conditions at the solid boundaries, as opposed to the use of uncertain estimates of solid surface roughness, and to an adequate representation of the viscous sublayer by the LES mesh used. It is crucial to allow mesh refinements adjacent to the bed and sidewalls as well as in the corner regions, and to ensure that the wall distance of the first node off a solid surface does not exceed unity, which is not the case in most of the existing LES applications to open-channel hydraulics. For the first time, this research thesis has explored practical LES strategies for accurate and efficient BSS predictions; these include the types of conditions imposed at the free surface and the ice cover underside, the lateral open boundaries at the upstream and downstream ends of a LES domain, and sensitivity tests. It has been demonstrated that the LES technique offers an attractive complement to laboratory measurements of BSS. With an exponential increase in computing power, it will eventually be feasible to perform LES for high Reynolds number flow in water channels.


identifier: Liu, Zhixiang  (2016) Reliable and Safe Motion Control of Unmanned Vehicles.  PhD thesis, Concordia University.

abstract:
Unmanned vehicles (UVs) are playing an increasingly significant role in modern daily life. In the past decades, numerous commercial, scientific, and military communities across the world are developing fully autonomous UVs for a variety of applications, such as environmental monitoring and surveillance, post-disaster search and rescue, border patrol, natural resources exploration, and experimental platforms for new technologies verification. The excessive opportunities and threats that come along with these diverse applications have created a niche demand for UVs to extend their capabilities to perform more sophisticated and hazardous missions with greater autonomy, lower costs of development and operation, improved personnel safety and security, extended operational range (reliability) and precision, as well as increased flexibility in sophisticated environments including so-called dirty, dull, harsh, and dangerous missions.

In order to successfully and effectively execute missions and meet their corresponding performance criteria and overcome these ever-increasing challenges, greater autonomy together with more advanced reliable and safe motion control systems are required to offer the critical technologies for ensuring intelligent, safe, reliable, and efficient control of UVs in the presence of disturbances, actuator saturation, and even actuator faults, especially for practical applications.

This thesis concentrates on the development of different reliable and safe motion control algorithms/strategies applicable to UVs, in particular, unmanned aerial vehicles (UAVs) and unmanned surface vehicles (USVs). A number of contributions pertaining to the fault detection and diagnosis (FDD), fault-tolerant control (FTC), disturbance estimation and compensation, and actuator saturation avoidance have been made in this thesis. In addition to the control problems, this thesis also presents several guidance-related contributions, including adaptive observer-based line-of-sight (LOS) guidance law, time-varying lookahead distance scheme, piecewise path switching criterion for guiding a single UV, as well as a proportional-integral (PI) type of leader-follower formation guidance strategy for a group of UVs.


identifier: Ketterer Hobbis, Stephanie  (2016) An Ethnographic Study of the State in Rural Solomon Islands (Lau, North Malaita): A Quest for Autonomy in Global Dependencies.  PhD thesis, Concordia University.

abstract:
This thesis is based on ethnographic fieldwork in Solomon Islands capital, Honiara (four months), and in the rural Lau Lagoon, Malaita Province (eight months). It examines how the Solomon Islands state, marked by a recent history of civil conflict and foreign military intervention, becomes visible in the everyday lives of rural and, to a lesser degree, urban non-elites; and how this visibility affects non-elite perceptions of the state as legitimate, dominant governing system. Non-elites are defined as those Solomon Islanders who often have only completed some primary/secondary education, whose first and primary language is their vernacular, and whose affluence is defined by their reliance on slash-and-burn agriculture, non-industrial fishing and micro-economic activities. Theoretically, this thesis draws on literature that defines the state through its ability to become invisible in everyday routines in such a way that state legitimacy and dominance as governing system are rarely questioned, and if they are only during temporary disruptions.

I propose that to understand to what extent and how the Solomon Islands state is integrated into everyday routines it is necessary to focus on mundane encounters with the state, its infrastructures and representatives as well as available alternatives; and to do so by prioritizing the perspective of the non-elites rather than the perspective of the disciplining state and state-focused members of (an urban) civil society. The Solomon Islands case is ideally suited for such an analysis because in this historically, linguistically and culturally diverse country the centralized state has been found to continuously struggle with diverging local conceptualizations of government and governance. My findings highlight that the Solomon Islands state has failed to become integrated into daily routines. Instead it is nearly continuously visible as a disruptive force. As a result non-elites continue to defy state-based unification and instead seek relative autonomy from the state by emphasizing the dominance and legitimacy of village-centric governance. This quest for autonomy is, however, increasingly curtailed by dependency on foreign foods and goods, and therein by a dependency on the state as primary globally-recognized legitimate mediator of economic relations.


identifier: Abbasi-Garravand, Elham  (2016) Using Pressure Retarded Osmosis Technology to Generate Salinity Gradient Energy (Osmotic Power) as a New Renewable Energy Source: Pretreatment to Reduce PRO Membrane Fouling.  PhD thesis, Concordia University.

abstract: As the population increases, the demand for electricity has also increased. Most of the required electricity is produced by burning fossil fuels at power stations all over the world which has dangerous influences on climate.  Therefore, it is important to produce new renewable and maintainable energy sources to decrease the use of fossil fuels. Osmotic power is a renewable source of energy that is generated by using salt and fresh waters. Pressure retarded osmosis (PRO) is a membrane based technology that can produce osmotic power. One of the main challenges for generating osmotic power by using PRO technology is the membrane fouling which reduces the permeate flux and consequently increases the cost and decreases the osmotic power generation. In this research, various pretreatment methods such as different types of ultrafiltration systems and a sand filter were used for removing total organic carbon (TOC), turbidity, and hardness from raw water. Moreover, different feed waters with various qualities were used to investigate the effect of fouling on a commercial membrane in PRO mode in continuous conditions. In addition, two physical and chemical cleaning methods were used to investigate and determine the desirable cleaning methods in PRO processes in order to control and reduce the membrane fouling. Most of the tests were performed at LTE Hydro Québec located at Shawinigan and the rest were performed at Concordia University. Based on the results, highest removal efficiency of turbidity occurred at 3.72 NTU and was 100% and 68.6% for ultrafiltration and the multimedia sand filter, respectively. Maximum TOC removal in ultrafiltration multimedia sand filter was 41% and 1.5% at 6.62 mg/L TOC initial concentration respectively. According to the results, the fouling rate when the draw solution was synthetic salt water followed the order of: untreated river water > multimedia sand filter > microfiltration > ultrafiltration effluents. It was observed that complete blocking, cake filtration and cake enhanced osmotic pressure were the main fouling mechanisms that governed the membrane fouling. The main inorganic foulants using synthetic salt water were iron, aluminum, calcium, sodium, and silica and when sea water was used as the draw solution, iron, aluminum, silica, magnesium, calcium, sodium and potassium were detected as inorganic foulants. The organic foulants were humic substances, polysaccharides and proteins from use of both synthetic salt water and sea water as draw solutions. The successful cleaning method was chemical cleaning using a combination of acidic and basic cleaners. This research indicates that using appropriate pretreatment and membrane cleaning methods can decrease the membrane fouling in PRO processes and consequently can improve the osmotic power generation.


identifier: Tang, Ting  (2016) The effect of celebrity on brand attachment: social media celebrity or well-known celebrity?  Masters thesis, Concordia University.

abstract: Previous academic research has focused on the effect of the celebrity on brands by examining their characteristics and their congruence with brands. The aim of this paper is to reveal the effect of psychological distance on self-concept and how it determines brand attachment. We additionally compare two types of celebrities to reveal the different consequence. We suggest that actual self-congruence (vs. ideal self-congruence) increases psychological proximity, leading to higher consumer-celebrity attachment and brand attachment. In particular, we argue that social media celebrities (vs. well-known celebrity) can decrease psychological distance with consumers and boost brand attachment. We detected participants’ familiarity with the celebrities and assigned them to different conditions to examine their self-concept, psychological distance, attachment to celebrities and brand attachment. Findings show that consumers’ actual self-congruence and ideal self-congruence negatively influences psychological distance. The less the psychological distance between celebrities and consumers, the higher the consumer-celebrity attachment and brand attachment. Furthermore, consumers perceive higher actual self-congruence and lower psychological distance with social media celebrities. Social media celebrities also present significant difference with well-known celebrities in emotional brand attachment. In terms of managerial implication, companies should highlight celebrity’s actual self and ideal self in order to diminish their psychological distance between consumers and celebrities. Moreover, if the brand advocates the actual self-image of target customers, partnering with social media celebrities would be a superior choice. This strategy would not only generate higher emotional attachment than using main stream celebrities, it would also save the brand on costly endorsement fees.


identifier: lim, chaewoon  (2016) Application of vibration-based techniques for modal identification and damage detection in structures.  Masters thesis, Concordia University.

abstract:
All structures such as bridges, buildings and dams are deteriorated by environmental conditions like corrosion, earthquake and traffic after they are built. Therefore, vibration-based damage identification (VBDI) techniques have attracted attention to verify the safety and functionality of structures. Conventional damage identification techniques such as non-destructive evaluation (NDE) methods have many obstacles and are not practical to be implemented in order to detect damage. One of the main obstacles is that the conventional methods are focused on local structural damage and easily affected by measurement noise. Moreover, there are several uncertainties that restrict the successful application of the damage detection. On the other hand, vibration-based techniques can be used when the global vibration characteristics is available. To do this, it is required to perform modal identification, perform model updating, and detect local changes in a structure.
The objectives of this study are: (a) to develop vibration-based techniques for modal identification by output-only information through the experimental and numerical study of bridges and frame structures; and (b) to study the VBDI techniques to perform model updating and damage detection using the changes in the dynamic characteristics of structures and determine their performance in practical structures.
Two existing bridges, a Pre-stressed Concrete Bridge (PSCB) and a Steel Box Bridge (STB) tested earlier were used here as case studies and the data from the vibration test were used to verify modal identification using output-only information. In this study, two output-only methods, Frequency Domain Decomposition (FDD) and Stochastic Subspace Identification (SSI) were studied to compare the results from the vibration test. In addition to this, laboratory experiments on three-story steel frame were carried out to generate additional data for testing the system identification and model updating methods. Further, various damage scenarios were created in the frame to obtain the vibration signals corresponding to such conditions. The vibration data from the undamaged and damaged frame were used to study the performance of existing VBDI methods.
Based on the above study, it is concluded that both FDD and SSI techniques provide accurate results for modal identification in the case of studied structures. FDD is relatively simpler, but it may miss some modal information when two modes are closer. However, in the cases studied here, the modes are quite apart from each other. Among many available VBDI methods, the matrix update method performs better than others when the measurement noise is small. Otherwise, data-driven models such as those based on Genetic Algorithm should be used.


identifier: Papachristou, Anastasios  (2016) An experimental and numerical investigation of predictive control with different building-integrated thermal storage systems.  Masters thesis, Concordia University.

abstract:
This thesis presents a numerical and experimental investigation of predictive control with different building-integrated thermal storage systems. The purpose is to utilize efficiently the available thermal mass of a space in order to reduce the peak demand and energy consumption while maintaining occupant comfort.
Two case studies are performed together with model development. The first one is a zone of a perimeter office with floor heating, convective cooling and a carpeted concrete floor. Various floor configurations are simulated to study the effect of thermal mass and its cover in predictive control. The window to wall (WWR) ratio is 75%, resulting in high solar gains. These solar gains are useful in winter but in summer they need to be reduced by controlling the shades to reduce total cooling load. The simulations results show that an exposed concrete floor (no carpet) can lead to significantly lower peak (about 35% in cooling and 41% in heating) in the auxiliary cooling/ heating as compared to a carpeted floor.
The second case study presents a simulation and experimental implementation of simple predictive control strategies in a test cell using a phase change material (PCM) as a means of thermal storage exposed to simulated outdoor conditions in a large environmental chamber. The PCM, embedded in a wall of the test cell, is actively charged through forced air circulation. The objective of the study is to investigate how model predictive control (MPC) can be used to leverage the thermal capacity of a PCM wall. This study also shows how a low-order thermal network model can be used as an effective tool in the design of the MPC strategy. The proposed MPC algorithm uses a set of linear ramp functions to change the room temperature setpoint to reduce and shift peak power demand. These ramp setpoint profiles allow the effective charging and discharging of the wall-integrated PCM. The algorithm applied in the experimental facility uses the outdoor temperature as input to select the best charging and discharging rates over a prediction horizon. A low-order model of the room and the PCM wall is used in the predictive control algorithm. It was found that this model can predict accurately the peak power demand and the temperature profile in the room. As the process moves forward in time, the weather profile is updated periodically and the algorithm calculates the new outputs over the new control horizon. The whole procedure is automated and the outputs of the algorithm are transferred to the local variables of the controller of the test room through BACnet.


identifier: Delvadiya, Chirag  (2016) Dynamic analysis of tapered circular discs made of isotropic and orthotropic materials using Rayleigh-Ritz method and ANSYS.  Masters thesis, Concordia University.

abstract:
Tapered rotating circular disc provides advantages of preferred stress state compared to the uniform-thickness circular disc rotating at the same speed. Hence, linearly-tapered circular disc and circular disc with hyperbolic profile along radial direction, often known as Stodola’s disc, are increasingly being used in many engineering applications such as in automobiles, turbomachinery, steam turbines, flywheels, and space structures. It is important to study the in-plane dynamics and out-of-plane dynamics of such circular discs as they play a vital role in causing vibration and noise. Design of circular disc for such applications also requires the knowledge of three-dimensional bending vibration characteristics of the disc. The present thesis aims at developing a generalized formulation and then to investigate the three-dimensional in-plane and out-of-plane vibration characteristics of uniform-thickness circular annular disc, linearly-tapered circular annular disc, and Stodola’s disc with clamped-free boundary condition.
The trigonometric functions in circumferential coordinate are employed in all the three displacement components in Rayleigh-Ritz method to calculate the natural frequencies. The numerical approach based on Rayleigh-Ritz method with finite-element-like modification has been developed to study the free vibration behaviour of the tapered circular discs made of isotropic and orthotropic materials and of clamped-free boundary condition. Numerical and symbolic computations have been performed using MATLAB and MAPLE software. The results for natural frequencies have been validated using Finite Element Method using ANSYS and results from previous literature wherever available. A comprehensive parametric study is conducted to study the effects of various design parameters.


identifier: Komeili, Matin  (2016) Large Eddy Simulation of Vertical AxisWind Turbine for Low Reynolds Number Applications.  PhD thesis, Concordia University.

abstract:
Research of low to intermediate Reynolds numbers flows (1000 < Re < 1000000) has become essential in the last two decades due to increasing interest in small Unmanned Aerial Vehicles (UAVs), small wind turbines, and exploration of planets such as Mars. Simulation of many of these applications need an accurate prediction of aerodynamic forces within five percent accuracy. Therefore, developing high accurate Computational Fluid Dynamics (CFD) tools is essential to design and optimize these systems.
Simulation of a Vertical Axis Wind Turbine (VAWT) on Mars is considered as the motivating application in this project. It is motivated by current plans of sending humans to Mars in the next two decades, and the need to investigate sustainable way to generate power on the planet.
VAWTs have a simple geometry but the flow structure around the blade is known to be one of the most complex flow in aerodynamics. Separation, vortex shedding and dynamic stall frequently occurs on the turbines’ blade. Therefore a tool that accurately simulates the flow around wind turbines, accurately, is needed.
Large eddy simulation has proven to be a reliable turbulence model with the capability of simulation flows with regions of separation and transition to turbulence. Growth of the computational capability along with development of more accurate numerical methods and new advanced LES models has permitted the use of wall-resolved LES.
In the current dissertation, Wall-Adapting Local Eddy-Viscosity (WALE) simulation is used to simulate flow around a vertical axis wind turbine. Using a second-order accurate discretization technique, both in space and time, with a low-dissipative method, enforced by an adjustable upwinding factor, achieves the required accuracy in Large Eddy Simulation. The proposed approach enables us to accurately predict the shear stress and pressure distribution on the blade. Therefore, dynamic stall location is spotted precisely.
The potential to increase the performance of small VAWTs by using Morphing blades are very promising. An in-house code has been extended to simulation flow around dynamically morphing blades. Therefore, Arbitrary Lagrangian Eulerian (ALE) is used to preserve the second order accuracy of the numerical scheme under a dynamic mesh, and a combination of spring and diffusion methods is used to adjust the mesh dynamically around deforming blades. A morphing blade scenario is presented to show the new capability developed.


identifier: Faille-Lefrançois, Julien  (2016) Chroniques d’une guerre sainte, création littéraire, précédée d’une analyse des processus de communication narratifs dans En attendant le vote des bêtes sauvages d’Ahmadou Kourouma.  Masters thesis, Concordia University.

abstract: Le concept de polyphonie romanesque développé par Mikhaïl Bakhtine suppose, dans le cadre d’une œuvre littéraire, l’expression de voix (de l’auteur et des personnages) tout aussi signifiantes et indépendantes les unes que les autres. Alors que la littérature postcoloniale africaine se voit régulièrement étiquetée polyphonique, le cas d’un roman comme En attendant le vote des bêtes sauvages d’Ahmadou Kourouma, dont les narrateurs intradiégétiques évoluent dans le contexte d’une dictature et font l’objet de répression, suscite un certain nombre de questions. Ce mémoire procède à l’analyse des processus de communication narratifs à l’œuvre dans le roman afin de mieux cerner les contours de la polyphonie kouroumalienne. La création littéraire Chroniques d’une guerre sainte nous transpose dans un autre contexte sociopolitique, celui d’une démocratie occidentale à l’ère du numérique. Cette fiction qui se déroule au Pays des Érables explore la question des libertés d’opinion et d’expression dans un environnement technologique permettant, par l’intermédiaire des médias sociaux et des plateformes numériques, l’expression d’un nombre illimité de voix. Prenant pour cadre les coulisses d’un parti politique en campagne électorale, Chroniques d’une guerre sainte témoigne de la réalité quotidienne d’un rédacteur politique. Cette création jette un éclairage nouveau sur le coût démocratique des stratégies de communication qui poussent les partis à resserrer leur contrôle sur les messages qu’ils véhiculent dans les médias numériques et traditionnels.


identifier: Marzbali, Mason  (2011) Penetration of Circular and Elliptical Liquid Jets into Gaseous Crossflow: A Combined Theoretical and Numerical Study.  Masters thesis, Concordia University.

abstract: A combined theoretical and numerical study of liquid jet deformation discharged perpendicularly into a subsonic transverse gas flow is carried out. Near-field trajectory of the jet is determined from an analytical approach for momentum flux ratios up to 100. Force balance on liquid element is analyzed in free stream direction assuming that surface tension and viscous forces are small compared to the aerodynamic force acting on the liquid column. Mass shedding from jet surface and liquid evaporation are neglected; therefore, the jet cross-sectional area and the jet velocity are invariable. A logarithmic correlation for the trajectory of elliptical liquid jets is proposed that takes into account the liquid to gas momentum ratio and drag coefficient. The changes in freestream properties and the gas velocity are incorporated in terms of the drag coefficient. In the numerical part, the drag coefficients of elliptical profiles with various aspect ratios are formulated based on the gas Reynolds number using a two dimensional model. The trajectories of elliptical jets with various aspect ratios are calculated based on the obtained drag coefficients. It is shown that the jets with lower aspect ratios penetrate more into the crossflow.  Furthermore, the deformation of a circular liquid jet subject to a gaseous crossflow is simulated using a three dimensional model. Volume of Fluid method is employed to capture the interface between the two phases and the first moment of closure is used to model Reynolds stresses in Reynolds Averaged Navier-Stokes equations. The deformations of the jet cross-section as the jet penetrates into the crossflow are illustrated. It is shown that the model is capable of resolving the Counter-rotating Vortex Pair (CVP) formed downstream of the jet.