identifier: Salam, Adil Muhammad  (2007) A parametric model to estimate design effort in product development.  Masters thesis, Concordia University.

abstract: The design and development of a product is a complex process, which requires many resources and various types of expertise. Because the process is complex, it is essential to estimate the design effort required to complete a product development project. The estimation of design effort is, in turn, a prime factor to predicting lead-time, cost, and effort requirements of a project. In this thesis, parametric models for estimating design effort are proposed. A case study involving engineering departments at Pratt & Whitney Canada (PWC) is presented. First, research is conducted on each of the design, aerodynamics, analytical and drafting departments at PWC to identify factors that could be best utilized in estimating design effort. Four factors are identified for parametric modeling. These factors are type of design, degree of change, concurrency, and experience of departmental personnel. The parametric model applied to each department uses least square regression. Furthermore, the jackknife technique is utilized to ameliorate the bias in regression equations coefficients. This research also uses a data masking technique in order to protect confidential data information of PWC. The masking technique enables to calibrate the impact of each factor considered in the parametric modeling, while not being affected by the masking. Data analysis is first utilized to establish regression based parametric models. Later, the regression equations are tested for their validation. It is found that the proposed parametric models provide good estimate of design effort when compared to the original estimates, with maximum relative errors of less than 10%. Furthermore, in each parametric model, the factors that significantly affect the design effort are identified using ANOVA table. Based on the outcomes reported in ANOVA, the number of factors is reduced and new models are developed with the reduced number of factors. Lastly, the application of the models, limitations and possible future studies are also discussed in this thesis.


identifier: Jin, Yu Lan  (2008) Simulation study of an estimator of bivariante survivor function and its variance estimator.  Masters thesis, Concordia University.

type: Thesis NonPeerReviewed

abstract: Bivariate survival data arises when we have either a pair of observation times for each individual or times on two related individuals, such as infection times for the two kidneys of a person or death times of twins. Such data are also often subject to censoring - bivariate censoring - i.e., exact observations may not be available on one or both of components because of drop-out or other reasons. Hence it is important to have an efficient, nonparametric bivariate survivor function estimator under censoring, i.e., a bivariate Kaplan-Meier estimator. In this thesis we carry out an extensive simulation study of an estimator proposed by Sen and Stute (2007), which involves solving for an eigenvector of a certain matrix. A comparison of the estimator with two other existing but unsatisfactory ones is also given using a small data-set. Moreover, variance of the former is computed using a bivariate analogue of Greenwood's formula, which involves solving a matrix equation of the form AXB=C


identifier: Al Maghayreh, Eslam  (2008) Avoiding state enumeration in dynamic checking of distributed programs.  PhD thesis, Concordia University.

abstract: Distributed programs are particularly vulnerable to software faults. Bugs in these programs are usually very hard to detect without automatic verification. The idea of checking an expected property in a given distributed program run (also referred to as runtime verification) has recently been attracting a great deal of attention for analyzing execution traces to ensure the reliability and dependability of distributed programs.  Due to concurrency, the number of global states of a distributed program run tends to grow exponentially with respect to the number of program statements executed. As a result, checking the satisfaction of a property in a given distributed program run can incur significant overhead. This thesis introduces various ideas and exploits them to develop efficient dynamic property checking algorithms. These include the use of atom, introducing and exploiting the notion of serialization and finally proposing a methodology that exploits the concept of atoms and partial order semantics to specify and to check properties of distributed programs.  The abstract specification of a distributed program can be mapped to the lower level implementation by labeling the code blocks that belong to the abstract functionalities of the program that are expected to be performed atomically. Each labeled code block is called an atom. Dynamically, an atom includes all the events that result from executing the selected statements from the corresponding code block. An efficient on-the-fly atomicity error detection algorithm has been developed. It is shown that if a run of a distributed program is atomic then the required properties can be checked on a reduced lattice, referred to as the atomic state lattice, which is significantly smaller than the original state lattice.  Even with atomization, the number of global states can still grow exponentially in the number of atoms executed. However, when a number of processes has to maintain a property, we expect that each process will be, at some point in time, aware of the events of other processes that may affect the property. Consequently, it is not necessary to check the property in each state. Only synchronized states, where processes have already exchanged the information necessary to maintain the property, need to be considered. These states can be characterized by a synchronization predicate. Serialization of synchronized states is the minimal avenue for a set of processes to exchange the necessary information to maintain a property. Two efficient algorithms to check the satisfaction of a property in a distributed computation in cases where the synchronization predicate is conjunctive or disjunctive have been developed.  Finally, a methodology based on the concept of atoms and a partially ordered multi-set (POMSET) model to specify and to check distributed programs properties has been proposed. The POMSET model promotes the separation of two different concerns in specifying and checking properties, namely, the ordering requirements and the computational requirements. A methodology to specify and to efficiently check the two requirements has been introduced.


identifier: Ramezanifard, Mohammadreza  (2008) Design and development of new tactile softness displays for minimally invasive surgery.  Masters thesis, Concordia University.

abstract: Despite an influential shortcoming of minimally invasive sugary (MIS), which is the lack of tactile feedback to the surgeon, MIS has increasingly been used in various types of surgeries. Restoring the missing tactile feedback, especially information which can be obtained by the palpation of tissue, such as detection of embedded lump and softness characterization is important in MIS. The present study aims to develop tactile feedback systems both graphically and physically.  In graphical rendering approach, the proposed system receives signals from the previously fabricated piezoelectric softness sensors which are integrated with an MIS grasper. After processing the signals, the tactile information is displayed by means of a color coding method. Using the graphical images, the softness of the grasped objects can visually be differentiated.  A physical tactile display system is also designed and fabricated. This system simulates non-linear material properties of different soft objects. The system consists of a linear actuator, force and position sensors and processing software. A PID controller is used to control the motion of a linear actuator according to the properties of the simulated material and applied force.  Graphical method was also examined to render the tactile information of embedded lumps within a soft tissue/object. The necessary information on the size and location of the hidden features are collected using sensorized MIS graspers. The information is then processed and graphically rendered to the surgeon. Using the proposed system surgeons can identify presence, location and approximate size of hidden lumps by grasping the target object with a reasonable accuracy.  Finally, in order to determine the softness of the grasped object, another novel approach is taken by the design and fabrication of a smart endoscopic tool equipped with sensors for measuring the applied force and the angle of the grasper jaws. Using this method, the softness/compliance of the grasped object can be estimated and presented to the surgeon


identifier: Bolourani, Golnoush  (2008) Evaluation of gas phase air cleaners for indoor environmental applications.  Masters thesis, Concordia University.

abstract: While granular activated carbon (GAC) filters have been used extensively for removal of contaminants from industrial gas streams, little research has been done on their adsorption capacity for indoor environmental purposes where ventilation systems are used to remove volatile organic compounds (VOC) contaminants and may allow higher air recirculation. This research investigates the performance of GAC filters for indoor environments by challenging them with various VOCs and subsequently measuring their removal efficiencies and breakthrough times.  A small environmental, closed-loop, dynamic test chamber was designed, constructed and used to measure the performance of eight different GAC filter samples when they were exposed to cyclohexane, ethyl acetate and toluene at different humidity levels. Three of the filters were composed of virgin activated carbon with granules of different sizes and/or shapes. The remainder filters were impregnated with either phosphoric acid or potassium hydroxide.  The breakthrough times and removal efficiencies of the filters were analyzed. Within the concentration range examined and at 50% relative humidity (RH), toluene exhibited the highest adsorption capacity on the filters, followed by ethyl acetate and cyclohexane. At 50% RH, the virgin filters were 25% more efficient in adsorbing the VOCs than the impregnated ones. For toluene, the 50% breakthrough times of filters 1A, 1B and 1C were 4, 0.13 and 0.03 hours, respectively, and the 80% breakthrough times were 5.60, 1.03 and 0.50 hours. respectively.  The effects of RH on adsorption of soluble (ethyl acetate) and insoluble (cyclohexane and toluene) VOCs on the performance of GAC filters were also investigated. The presence of water vapor in the chamber had little effect on the adsorption capacity of the toluene until about 50% RH. At 50% RH and above, an increase of 16.5% in adsorption capacity of ethyl acetate occurred, while the adsorption capacity of cyclohexane and toluene rapidly decreased. The 80% breakthrough times of filters IA, 2A and 3A for toluene decreased on average, up to 33%. 38% and 25%, respectively, when the RH increased from 30% to 70%. Therefore, competitive adsorption of VOCs with water vapor molecules shortened the breakthrough times of the filters for toluene and cyclohexane as the RH level increased.


identifier: Brion, Denis  (2007) Organic matter preservation in marine sediments : a bulk and molecular study.  PhD thesis, Concordia University.

abstract: Sedimentary organic matter (OM) composes 20% of all carbon preserved in the Earth's crust. Marine sediments constitute the major long-term sink of organic carbon (OC) on Earth, although only <0.3% of OM photosynthesized by plants is eventually preserved. While the burial of this small OM fraction affects the global cycles of atmospheric CO 2 and O 2 , the mechanisms that control sedimentary OM preservation are still unclear. Recent studies have suggested a strong relationship between OM preservation and the OM physical forms, chemical compositions and cumulative exposure to O 2 during deposition and burial. However, although organic geochemistry has now progressed to the point where the major hydrolysable biochemicals (proteins, carbohydrates and lipids) can be measured using standard chromatographic methods, >75% of sedimentary OM is still missed chromatographically and remains molecularly uncharacterized. We therefore combined bulk and molecular-level analytical approaches to target the mechanistic understanding of the effects of physical protection, molecular composition and O 2 exposure time (OET) on OM preservation. A wet chemical sequential extraction procedure was developed to quantify and separate OM from diverse marine sediments fractions having different chemical reactivity. This research project then focussed on one fraction believed to be determinant in OM preservation, i.e., non-hydrolysable oxygen-sensitive organic matter (OSOM). An optimized method based on the gentle chemical oxidation of OM using RuO 4 was developed in order to investigate the molecular structure of OSOM and its relationship to OM preservation under varying sedimentary conditions. The relative abundance of the OSOM fraction in marine sediments decreases exponentially with oxygen exposure time, in agreement with our working hypothesis. However, our data suggest a more complex relationship than previously thought in that inputs of terrestrially-derived OSOM most likely affect the degradation rate and relative abundances of the bulk OSOM fraction. RuO 4 treatment on the OSOM fractions revealed a composition consisting mostly of cross-linked aliphatics polyesters, and relative abundances of the oxidation products that are correlated with oxygen exposure time (OET). Further molecular, compound-specific isotopic (GC-IRMS) and spectroscopic (FTIR, solid-state HR-NMR) studies on the OSOM component will help verifying the hypothesis of the major role of oxygen exposure time in OM preservation.


identifier: Werbin, Kenneth C  (2008) The list serves : the apparatuses of security and governmentality.  PhD thesis, Concordia University.

abstract: Inspired by taxonomist Jack Goody's theorizing of 'ancient lists' as 'intellectual technologies,' this research analyzes listing practices in modern and contemporary formations of power, and how they operate in the installation and securing of the uncertain political economic milieus of circulation that characterize Michel Foucault's conception of governmentality. Propelling the list's critical operations in the delimitation and policing of 'threatening' movements from out of modern history, and into a contemporary analysis of power, this research demonstrates how the correlation of computer, statistical, and list technologies and techniques first installed under the Nazi regime , continues to factor significantly in the segmenting and constitution of a most critical classification of contemporary homo sapiens : the terrorist class, or homo sacer . Indeed, in this analysis of how lists serve formations of power, Foucault's populations and milieus of circulation installed through the apparatuses of security are reconciled with Giorgio Agamben's theorizing of 'bare life' as the fundamental political unit of modern and contemporary sovereignty. Investigating how lists served the emergence of modern computers , and continue to correlate power/knowledge in contemporary assemblages like no-fly lists ; as well as in a series of increasingly pervasive and ubiquitous watch-list conjunctures , this research characterizes the technoscientific cultural construction of the contemporary terrorist as a critical function of no-blank list culture . In this way, it is argued here that the list is not simply an innocuous tool of everyday life for administering the minutiae of mundane existence, but rather, operates as a security technology of contemporary governmentality--a critical support of juridical-disciplinary mechanisms and assemblages of police--with the dual role and double integration effect of self-elaborating and securing the classes of 'factual' knowledge it itself calls into 'truthful' reality.


identifier: Czerwonko, Michal  (2008) The stochastic dominance valuation of options under transaction costs : extensions, implementation and empirical tests.  PhD thesis, Concordia University.

abstract: In the first essay American call and put options on the S&P 500 index futures that violate the stochastic dominance bounds of Constantinides and Perrakis (CP, 2007) over 1983-2006 are identified as potentially profitable investment opportunities. Call bid prices more frequently violate their upper bound than put bid prices do, while evidence of underpriced calls and puts over this period is scant. In out-of-sample tests, the inclusion of short positions in such overpriced calls, puts, and, particularly, straddles in the market portfolio is shown to increase the expected utility of any risk averse investor and also increase the Sharpe ratio, net of transaction costs and bid-ask spreads. The results are strongly supportive of mispricing and also strongly supportive of the CP bounds as screening mechanisms for mispriced options.  The second essay introduces a result for call lower bound more powerful that the one applied in the first part of this thesis. The Proposition 5 call lower bound in Constantinides and Perrakis (2002) is shown to have a non-trivial limit as the time interval tends to zero. This establishes the bound as the first call lower bound known in the literature on derivative pricing in the presence of transaction costs with a non-trivial limit. The bound is shown to be tight even for a low number of time subdivisions. Novel numerical methods to derive recursive expectations under a Markovian but non-identically distributed stochastic process are presented.  The third essay relaxes an assumption in the first part of this thesis on the optimal trading policy in the presence of transaction costs. We derive the boundaries of the region of no transaction when the risky asset follows a mixed jump-diffusion instead of a simple diffusion process. These boundaries are shown to differ from their diffusion counterparts in relation to the jump intensity for lognormally distributed jump size. A general numerical approach is presented for iid risky asset returns in discrete time. An error in an earlier published work on the region of no transaction for discretized diffusions is demonstrated and corrected results are presented. Comparative results with a recent study on the same topic are presented and it is shown that the numerical algorithm has equally attractive approximation properties to the unknown continuous time limit.


identifier: Pai, Hsueh-ieng  (2008) Uncertainty management for description logic-based ontologies.  PhD thesis, Concordia University.

abstract: Description Logics (DLs) play an important role in the Semantic Web as the foundation of ontology language OWL DL. The standard DLs, based on the classical logic, are more suitable to describe concepts that are crisp and well-defined in nature. However, for many emerging applications, we also need to deal with uncertainty. In recent years, a number of proposals have been put forward for incorporating uncertainty in DL frameworks. While much progress has been made on the representation and reasoning of the uncertainty knowledge, query optimization in this context has received little attention.  In this thesis, we tackle this problem in both theoretical and practical aspects by taking a generic approach. We first propose the [Special characters omitted.] framework which extends the standard DL [Special characters omitted.] with uncertainty. This is done by extending each component of the [Special characters omitted.] framework, including the description language, the knowledge base, and the reasoning procedure. In particular, the resulting semantics of the description language is captured using the certainty lattice and the combination functions. The knowledge base is extended by associating with each axiom and assertion a certainty value and a pair of combination functions to interpret the concepts that appear in the axiom/assertion. A sound, complete, and terminating tableau reasoning procedure is developed to handle such uncertainty knowledge bases. An interesting feature of the [Special characters omitted.] framework is that, by simply tuning the combination functions that are associated with the axioms and assertions, different notions of uncertainty can be modeled and reasoned with, using a single reasoning procedure.  Using this framework as the basis, we then investigate optimization techniques in our context. We adapt existing optimization techniques developed for standard DLs and other software systems to deal with uncertainty. New techniques are also developed to optimize the handling of uncertainty constraints generated by the reasoning procedure.  In terms of practical contribution, we developed a running prototype, URDL - an Uncertainty Reasoner for DL [Special characters omitted.] , which implements the proposed optimization techniques. Experimental results show the practical merits of the [Special characters omitted.] framework, as well as the effectiveness of the proposed optimization techniques, especially when dealing with large knowledge bases.


identifier: Chen, Rui  (2008) An enhanced Web robot for the CINDI system.  Masters thesis, Concordia University.

abstract: With the explosion of the Web, traditional general purpose web crawlers are not sufficient for many web traversing and mining applications. Consequently, focused web crawlers are gaining attention. Focused web crawlers aim at finding web pages only related to the pre-defined topic at much less storage and computing cost. It is inherently suitable for the construction of digital libraries. As an essential part of Concordia INdexing and DIscovering system (CINDI) digital library project, CINDI Robot is a focused web crawler digging and collecting online academic and scientific documents in computer science and software engineering field.  In this thesis, we discuss the details of building a multi-threaded, large-scale, intelligence-based focused web crawler, CINDI Robot. To enhance CINDI Robot, some state-of-the-arts techniques are exploited or modified to accommodate our task. The naïve Bayes classifier and the Support Vector Machine classifier are utilized to contribute to the classification; a revised context graph algorithm and a special tunneling strategy are employed to increase recall; URL ordering policies are set up to sort all crawling web pages. Other heuristics obtained during the experimental stage are also incorporated into the final version of the CINDI Robot. Finally we form a multi-level inspection infrastructure to efficiently traverse the Web. Through this multi-level inspection scheme, text features of web page contents, URL patterns and anchor texts are considered together to guide crawling processes. Our experiments demonstrate that the final version of our CINDI Robot outperforms traditional web crawlers in terms of precision, recall and crawling speed.


identifier: Haddad, Chedid  (2008) CINDI_QA : a template-based bilingual question answering system.  Masters thesis, Concordia University.

abstract: CINDI_QA is the result of the CINDI group's efforts at tackling multilingual Question Answering. The goal of the system is to receive a French question and return the answer to that question in English.  This thesis outlines the architecture of CINDI_QA and how it is integrated with several open-source tools. Google Translate is used to produce the English equivalent of the French question. The Link Parser is a semantic parser of English that identifies keywords such as nouns, verbs and adjectives. WordNet is a lexical analyzer that generates synonyms of those keywords. Finally, Lucene handles indexing and searching of the large data collection made up of Wikipedia static pages.  In addition to these tools, CINDI_QA heavily relies on templates to better understand the question entered by the user. Six templates help the system answer questions about different subjects.  The performance of CINDI_QA has been assessed by participating in the 2007 edition of the QA@CLEF competition, an annual conference focusing on multilingual QA, to which the CINDI group submitted two runs that ranked second and third out of eight candidates


identifier: Gonzalez, Alex M  (2008) Implementation of ISO standards through formalization of requirements for process management.  Masters thesis, Concordia University.

abstract: Companies always seek ways to increase their competitiveness and performances by implementing defined quality methodologies. The present thesis aims at providing companies with a methodology that identifies specific requirements for process management using ISO standards (IST).  IST implementation can be very costly. This is due to the fact that it requires specific knowledge, resources (financial, time and others) as well as motivation on the part of organizations to pursue ISO certification. The present thesis provides a specific methodology to identify IST requirements. This methodology uses a different approach to carry out the necessary interpretation. Its advantages lie in its reduction of the apprehension time and in the enhancement of its overall understanding.  Furthermore, the present thesis proposes an effective approach for IST implementation by applying a methodology called Environment Based Design (EBD) theory and a model called Quality Implementation Practical Flowchart (QIPF).  In EBD a graphical language called Recursive Object Modeling (ROM) is developed to design the graphical representation of IST requirements, thus, providing an easy and unambiguous understanding of ISO standards' clauses. The development of QIPF involves a methodology based on on-site experience. Thus, IST requirements defined into a formal structure are taken as the starting point for developing the implementation process.  An example based on the analysis established in the present document is used to show how an IST implementation can be developed


identifier: Gherbi, Abdelouahed  (2007) Modeling and analysis of real-time software systems using UML.  PhD thesis, Concordia University.

abstract: Real-Time Systems (RTS) should not only function correctly but should also satisfy time constraints. RTS include embedded systems, which are used nowadays in a variety of applications. These are, for instance, house appliances, automotive, aeronautic/aerospace, and health monitoring systems, to mention just a few. The design of such systems is complex and challenging. In order to cope with the complexity of RTS, there is shift in their development to follow a model-driven approach, such as the Model Driven Architecture (MDA), which relies on using models of high level of abstraction. The Unified Modeling Language (UML) is the Object Management Group (OMG) standard modeling language to support MDA. UML is appropriate for software systems because it allows for a multi-view modeling approach through its multitude of diagrams covering the structure, the behavior and the deployment architecture. Moreover, UML is also used in the domain of real-time software systems. This is achieved through its profiles, including, the OMG standard profile for Schedulability, Performance and Time (UML/SPT) or the upcoming standard UML Profile for Modeling and Analysis of Real-Time and Embedded Systems (MARTE). However, UML modeling faces some challenging issues such as model consistency. This issue becomes worse in the context of real-time software systems because additional aspects should be taken into consideration, including time, concurrency and schedulability. In this thesis, we address several issues related to modeling and validation of RTS with UML. We focus in particular on the consistency of UML/SPT models. We adopt an incremental approach to check the consistency of these models by distinguishing the syntactic and semantic levels. The latter is further decomposed into behavioral, concurrency-related and time consistency. Our contributions in this thesis are fourfold. First, we leverage the extensibility mechanisms of UML to propose an extension to UML/SPT. This extension enables the modeling of multicast communications, which is required for the description of the behavior of certain real-time protocols. Second, we propose a formalization of the concurrency modeling capability in UML/SPT using timed automata. This formal semantics allows for applying well-established model checking techniques to check concurrency related consistency in UML/SPT models. Third, we propose an MDA-compliant approach to enable schedulability analysis of UML/SPT models. We present a proof of concept for this approach through a prototype implementation using the Atlas Transformation Language (ATL) and XML-based technologies. Finally, we use the schedulability analysis applied to UML/SPT models in order to check the time consistency of a system design modeled by means of a set of state machines with respect to time constraints modeled using a set of sequence diagrams annotated with UML/SPT time stereotypes.  Keywords : Real-time systems, Model-driven Architecture, UML, UML/SPT, Model transformation, ATL, XML, XSLT, Consistency, Concurrency, Model Checking, Schedulability Analysis.


identifier: Pan, JiangJing  (2008) Multi-resolution fault diagnosis in discrete-event systems.  PhD thesis, Concordia University.

abstract: In this thesis, a framework for multi-resolution fault diagnosis in discrete-event systems (DES) is introduced. Here a sequence of plant models, with increasing resolution, are used in fault diagnosis and the range of possible diagnosis is narrowed down step by step, until the failure node is isolated. In this way, the original problem of fault diagnosis is replaced by a sequence of smaller problems. The plant models used at each step of diagnosis are abstractions of the original plant model. We propose to use model reduction through the solutions of the Relational Coarsest Partition problem to obtain these abstractions. For each diagnosis step, minimal sensor sets are chosen to have a coarser output map, and hence, to improve the efficiency of model reduction.  In this thesis, a polynomial algorithm is proposed that verifies failure diagnosability by examining the distinguishability of two plant (normal/faulty) conditions at a time. A procedure is presented that finds minimal sensor sets, referred to as minimal distinguishes for distinguishability of one condition from another. A polynomial procedure is introduced that combines minimal distinguishers to obtain a minimal sensor set for fault diagnosis. The proposed method reduces the computational complexity of sensor selection.  A benefit of using minimal distinguishers is that their computation maybe speeded up using expert knowledge. The proposed method for sensor selection is particularly suitable for multi-resolution diagnosis since it permits some of the results of computations, performed for sensor selection at the lowest (finest) level of multi-resolution diagnosis to be reduced at higher levels. This feature is particularly useful in reducing the computations necessary for online reconfiguration of the multi-resolution diagnosis system.  An important procedure used in sensor selection is testing diagnosability. In this thesis, a new procedure for testing diagnosability in timed DES is introduced based on the relatively timing of plant output sequence. It is shown through example that the proposed test maybe executed with significantly fewer computations compared to tests developed for untimed models and adapted for timed systems. Furthermore, two new sets of sufficient conditions are provided under which diagnoser design and diagnosability tests based on relative timing of output sequence can be performed efficiently


identifier: Aljarrah, Mohammad  (2008) Thermodynamic modeling and experimental investigation of the Mg-Al-Ca-Sr system.  PhD thesis, Concordia University.

abstract: In this work, a self-consistent thermodynamic database for the Mg-Al-Ca-Sr system using the modified quasichemical model has been constructed. The thermodynamic description of the quaternary system was established by combining the thermodynamic descriptions of the constituent binary and ternary sub-systems. The Mg-Al-Ca and Mg-Al-Sr systems were investigated by combining thermodynamic modeling and experimental investigation. The experimental investigation has been performed using DSC, XRD, SEM and EPMA. Also, isothermal sections at 300°C and 400°C were constructed for the Mg-Al-Ca and Mg-Al-Sr systems. In the Mg-Al-Sr system, six ternary solubilities of the binary compounds extended into the ternary system have been found and denoted as (Mg 17 Sr 2 ), (Mg 23 Sr 6 ), (Mg 38 Sr 9 ), (Mg 2 Sr), (Al 4 Sr) and (Al 2 Sr). The reported ternary compound in the literature (Mg 58 Al 38 Sr 4 ) has been observed in this work. In the Mg-Al-Ca system, three binary compounds were found to dissolve the third component in the ternary system and were denoted as (Al 2 Ca), (Al 3 Ca 8 ), and (Mg 2 Ca). The ternary compound (C36) reported in the literature has been confirmed.  A comparison between the calculated liquidus projection of the Mg-Ca-Sr system using the modified quasichemical model and random solution model has been presented. It was found that while the random solution model agrees well with the experimental phase diagram, the modified quasichemical model gives better agreement with the experimental thermodynamic data and the experimental phase diagram.  Liquidus projection of the Al-Ca-Sr system was calculated using the modified quasichemical model and combined with the other three ternaries in one database for the Mg-Al-Ca-Sr system.


identifier: Parsa, Armin  (2008) Electromagnetic analysis of a finite reinforced concrete slab.  PhD thesis, Concordia University.

abstract: In order to calculate the electromagnetic fields reflected, transmitted, and diffracted by a finite reinforced concrete slab in the presence of a source, a Green's function/method of moments approach has been developed. In doing so, a Green's function solution for a finite and electrically thick dielectric slab is obtained. The Green's function for the arbitrary position of the source and field point is based on the interior Green's function, i.e. the Green's function when the source and the field point are both inside the slab. The solution is two-dimensional, with an electric line source excitation.  The first development in this thesis presents an interior electric field Green's function for a thick and finite dielectric slab. The presented solution is based on the separation of variables method which gives an exact solution to a separable slab. The separable slab is closely related to the finite slab. The separable slab solution is expressed in terms of the contribution of the surface wave modes plus the remaining part which is called the "residual wave"' contribution. In order to model a finite slab, the surface wave contribution of the separable slab is modified since the separable slab solution fails to model the finite slab when a surface wave mode is close to resonance. The modification is done by correcting the end cap reflection coefficient for each mode and accounting for the mode conversions. The mode conversions and reflections are characterized by the end cap scattering matrix which is obtained by the method of moments. As a result, the interior Green's function solution for a finite slab is the modified surface wave solution plus the residual wave contribution obtained for the separable slab. The Green's functions for the cases when the source and/or field points are outside the slab are obtained using the interior Green's function and the surface equivalence principle.  Having the finite slab Green's function, it is possible to model a finite reinforced concrete slab. Since the metallic rods are assumed to be electrically thick, each metallic rod is replaced by a circular array of thin wires complying with the "same surface area" rule of thumb. To obtain the unknown induced currents on the surface of the thin wires, the method of moments is used in conjunction with the finite slab Green's function. The model is used to investigate the reflection and transmission of electromagnetic waves for some cases of practical interest


identifier: Bossé, Patrick  (2008) Politiques d'un cinéma vers l'État-nation : hommage à notre paysannerie (1938) de l'abbê Albert Tessier.  Masters thesis, Concordia University.

abstract: L'activisme de l'abbé Albert Tessier passe ouvertement du régionalisme au nationalisme avec son film Hommage à notre paysannerie (1938). Dès 1913, Tessier immortalise sur pellicule les visages, les moeurs et les espaces de sa région de naissance, la Mauricie. Suite à sa nomination en 1937 à titre de visiteur officiel des Écoles ménagères, il voyage à travers la province de Québec en toutes saisons et en profitent pour capter de nombreuses images de sa patrie. Il constate une condition commune chez les paysans canadiens-français en toutes parts du territoire couvert. Avec son matériel filmique accumulé aux quatre coins de la province, il entame la création d'un portrait protoréaliste de la paysannerie canadienne-française. Son film lui servira à plus de 1 500 reprises lors de conférences éducatives pour révéler à chaque spectateur paysan, chaque public croyant, leur possibilité de vivre une vie saine, sainte et indépendante par l'agriculture en famille avec des structures efficaces dans leur village. Les lumières philosophiques de Platon, Aristote et Rousseau découvrent dans Hommage à notre paysannerie la forme d'une constitution divine réunissant les paysans et les membres du clergé comme citoyens autour d'une même foi, même voie. Des analyses séquentielles et par image expliquent la teneur des recommandations de Tessier à ses fidèles. L'apport théorique de Rancière révèle la qualité première recherchée par Tessier pour les paysans dans son projet national: le principe d'égalité. Hommage à notre paysannerie se confirme ainsi comme une véritable oeuvre d'art politique.


identifier: Donyaee, Mohammad K  (2008) Investigating the correlation of usability measures and user tests : a roadmap for a predictive model.  PhD thesis, Concordia University.

abstract: Most of the existing usability evaluation and testing methods require a fully functional prototype. As a consequence, tests are conducted after the development and most often, after the deployment of the whole software. Furthermore, tests require a costly usability laboratory and highly trained usability testers, usually developers lack training in conducting such tests. Cost-benefit studies show that these problems and similar ones result in significant costs. Predictive usability models have been introduced as potential solutions to address these crucial drawbacks of the existing usability evaluation methods. Predictive usability models and measures can supplement the existing evaluation methods while reducing costs and enhancing efficiency, accuracy and objectiveness of the tests.  In this thesis, we demonstrated via empirical investigations, that usability measures and user-oriented tests conducted by users can provide similar scores regarding the overall usability as well as two core usability parameters: Learnability and Efficiency. Moreover this thesis demonstrated that the results of empirical investigations can be used to build measure-based models for usability prediction. As an outcome, this thesis introduced a comprehensive methodology to develop and validate measure-based models for usability prediction from early user interface design artifacts including storyboards and prototypes. This methodology includes a systematic process that involves discovery of correlations between usability measures and the results of usability tests performed by users.


identifier: Swain, Sara  (2008) Roaming across cinematic space : the cell phone in narrative film.  Masters thesis, Concordia University.

abstract: This thesis stems from the increasing ubiquity of cell phones in the cinema. It attempts to register the changes that have occurred in cinema in the wake of cellular telephone technology by considering the narrative, stylistic and symbolic significance of the technology in different cinematic environments. This project focuses on the stalker film, the contemporary Japanese horror film, and the network narrative film through the examples of Wes Craven's Scream Trilogy (19%, 1997, 2000), Takashi Miike's Chakushin ari (2003), and Mike Figgis' Timecode (2000) respectively. Drawing on Avital Ronell's theory of telephonic subjectivity and Tom Gunning's work on the fixed telephone's affinity to film, it is argued that the cell phone's dimensions of mobility, mutability, ubiquity and constant touch have given rise to a new stage in telephonic logic. The case studies in this thesis reveal through close readings, how film exploits this new logic, seizing on the emergent modalities of networked subjectivity and hyperconnected spatial relations to make film more dynamic and socially relevant. Finally it is argued that an examination of this exploitation makes legible the cell phone's social and psychological implications in quotidian life.


identifier: McCord, Shane  (2008) Pushing books : the bookwork as democratic multiple in the late capitalist era.  Masters thesis, Concordia University.

abstract: This thesis examines the development of artist's books and other similar mass- produced art works in the codex form. More specifically, the object of investigation in this thesis focuses on the position of such art works as democratic multiples. This development is traced through three case studies on the works of Edward Ruscha (b.1937), the artist collective General Idea (1969-1995), and Matthew Barney (b.1967). The thesis argues that though artist's books are often characterized as being polemical towards capitalist production, these bookworks achieve their most democratic results when making use of the techniques of the capitalist market, rather than working against it.


identifier: Kirk, Allison  (2007) A syntactic account of split DPs in herodotus.  Masters thesis, Concordia University.

abstract: In Herodotus' Histories one finds instances of nominal elements which seem to form cohesive phrases but which are separated from one another by other intervening material. These interrupted phrases are referred to as 'discontinuous' or 'split' constructions. The presence of these discontinuous expressions makes the syntax of Herodotus' Greek seem radically different from that of languages like English. This paper intends to show that although Herodotus' Greek had certain freedoms of syntactic movements which are not overt in languages like English, the dialect in question displays a hierarchy of phrase structure. We will show that Herodotus' DP was richly discourse-oriented and that discourse related factors allowed for freedoms of movement which are not available in languages like English. The goal is to account for split sequences of DPs containing adjectives, quantifiers, demonstratives and WH- words, while at the same time restricting the possibilities of syntactic movements in order to account for constructions which are unattested in the text and are predicted to be ungrammatical by the theory here constructed.


identifier: Cyr, Rachel E  (2008) Traces, testimony, paranoia.  Masters thesis, Concordia University.

title: Traces, testimony, paranoia

abstract: Prior to 1984, human rights documentation consisted of eyewitness and victim testimony. Since then forensic science has become a staple of human rights investigations. The resurgence of positivism consequence of these institutional and procedural shifts inspired the metaphorical conflation of physical evidence and physical traces with narrative and personal testimony. This thesis considers this tropic drift within human rights discourse as an example and a reflection of the epistemological ambivalence and semiotic confusion that still surrounds the indexical sign both outside and within critical theory. This thesis argues first that traces constitute non-linguistic sign-events whose formal properties motivate anecdotal and narrative modes of explanation and second, that the growing cultural importance of forensic science reifies a form of paranoic knowledge at the heart of western subjectivity.


identifier: Cantin, Raymond  (2008) Les principes de développement des simulations éducatives peuvent-ils augmenter l'efficacité du e-learning? : une étude comparative de deux méthodes de développement.  Masters thesis, Concordia University.

abstract: Le e-learning est utilisé pour former les employés dans tes organisations depuis plus de trente ans. Mais son modèle de développement linéaire n'a pas démontré l'efficacité recherchée (Merill, Allen). En tant qu'industrie, le domaine serait déplorablement pauvre sur le plan des réalisations (Quinn, 2005). En plus, le taux d'abandon en e-learning des employés dans les organisations est de 75 pour cent (Hogg, 2002; Bernard et al., 2004). Plusieurs utilisent l'expression ±e-boring» (Allen, 2003).  Cette étude pilote ou étude de cas utilise un design quasi-expérimental (il ne s'agit pas d'une recherche exhaustive ou scientifique). Elle vise à valider si les principes de développement des simulations éducatives, lorsqu'ils sont appliqués au développement e-learning, peuvent en améliorer l'efficacité au niveau de l'apprentissage.  La méthode préconisée a consisté à développer deux versions d'un cours e-learning basées sur le même contenu, et d'exposer un groupe de cinq personnes à ces deux cours à l'aide d'un ordinateur. Nous avons ensuite récolté leur feedback à propos de la qualité de leur apprentissage.  La première version est du e-learning de type linéaire développé à partir de storyboards, telle qu'on en retrouve en industrie; l'autre version est de type simulation et est plus systémique.


identifier: Khan, Maria Palwasha  (2008) Coordinated rendezvous and surveillance for multiple unmanned aerial vehicles (UAVs) subject to actuator and sensor faults.  Masters thesis, Concordia University.

abstract: In this thesis, the problem of employing multiple UAVs for carrying out a Coordinated Strike and a Multiple UAV Surveillance mission has been addressed. The goal of the Coordinated Strike mission is for multiple UAVs to cooperate in order to simultaneously arrive at a high priority target to carry out a coordinated strike. The coordination strategy is based on coordination variables and coordination functions. A distributed system architecture is proposed that allows vehicles to communicate coordinating information across the team without reliance on a central ground controller. Simulations have been conducted to illustrate the performance of the coordination strategy under an actuator fault in single and multiple vehicles.  The Multiple UAV Surveillance problem has been investigated by developing a hypothetical Border Surveillance Mission, wherein a UAV team is tasked to monitor a region along a border between two countries. The goal of the UAVs is to cover the entire surveillance region, while minimizing the team cost, which is a function of each vehicle's fuel consumption and mission time. Three fault cases in a single vehicle in the team have been simulated, namely (1) actuator; (2) sensor; and (3) simultaneous actuator and sensor faults. These faults necessitate a resource allocation problem to be solved, which is used to determine the configuration of the team engaged in the surveillance mission. The team chosen to perform the surveillance mission is the one that incurs the minimum cost for performing the mission.


identifier: Choudry, A. A  (2008) NGOs, social movements and anti-APEC activism : a study in power, knowledge and struggle.  PhD thesis, Concordia University.

abstract: This thesis analyzes political struggles over power and knowledge within networks of non-governmental organizations (NGOs) and social movements contesting neoliberal globalization. Existing studies tend to obscure tensions, contradictions and differences among organizations and movements engaged in resistance and contest of neoliberalism. Situating 'globalization' as a contemporary manifestation of older processes of colonialism and imperialism, this work draws upon and extends institutional ethnography/political activist ethnography methodologies to explicate how 'anti-globalization' practice is socially organized. Starting from a standpoint in an everyday world of activist practice, this work examines NGO, activist and official documents, and insights from the author's 'insider' status as an activist/researcher in NGO conferences and campaigns. It explicates tensions and asymmetries of power within networks throughout the Asia-Pacific that mobilized to contest the Asia Pacific Economic Cooperation (APEC) forum in the 1990s. Combining a dual interdisciplinary academic and activist theoretical framework, it innovatively weaves knowledge and theory produced within social movements and activist milieus with academic scholarship. This work draws upon Marxist political economy and critical adult education traditions, critiques of dominant social movement theory, non-Western approaches to epistemologies of knowledge, organizational analysis, social history and other critical historiographies. It identifies and questions hegemonic NGO practices, arguing that hierarchies of power and knowledge within 'alternative' milieus often reproduce, rather than challenge dominant practices and power relations, and serve elite interests rather than those of constituencies which these organizations claim to represent. This thesis troubles the NGOization of political struggles, NGO claims of representation, and the privileging of professionalized NGO and academic knowledge at the expense of voices and histories from below. In so doing, it offers new conceptual resources for future scholarship on social movements and 'civil society', as well as tools to inform activism.


identifier: Oliver, Kristen  (2008) Reconstructing normal : women and the "problem" body.  Masters thesis, Concordia University.

abstract: Women are popularly portrayed in the media and in academic literature as being dissatisfied with their bodies (Garner, 1997). This prompted me to ask, given the dominance of the discourse of the 'problem' body, how 'problematic' is this dissatisfaction in the daily life of the average woman? I conducted life-history interviews with 20 women between the ages of 22 and 59. They revealed three ideal types of women, which I present as three groups. First, the "butterflies" focused their life stories on what they identified as a significant positive change in their overall perception of their bodies. Second, the "yo-yos" focused their narratives on their overall body dissatisfaction. Finally, the "holistics" shared narratives of overall body satisfaction and appreciation. Health, the 'problem' body, and aging were the dominant topics in the narratives of all the women, regardless of age or group. The interviews revealed that while some of the women were critical and dissatisfied with aspects of their bodies, all of the women reported at least minimal body satisfaction. What this means is that while the 'problem' body is real and present in the lives of these women, they are not spending their lives focused on their bodies, and in most cases body concerns take up little of their time.


identifier: Gabriela., De A. C. Abbud  (2008) Attentional requirements of walking according to the gait phase and onset of auditory stimuli.  Masters thesis, Concordia University.

abstract: The influence of an attention demanding cognitive task on each phase of gait was analyzed, using a dual-task paradigm. Electromyography (iEMG) from eight muscles from the dominant leg was collected from 23 participants (age 18-27) while walking on a treadmill at a 20% increase of their self-selected speed and while walking and performing a cognitive task. The cognitive task consisted of subtracting one (EASY) or seven (HARD) from numbers aurally presented. Reaction time (RT) and accurate responses of the cognitive task were recorded. iEMG events were selected according to stimuli onset (0-150 ms, 150-300 ms and 300-450 ms) prior to the phases of gait (double-leg, single- leg and swing). There was a decrease in iEMG amplitude of fibularis longus (p = .013) and vastus lateralis (p = .065) while walking and performing the cognitive task. When stimulus onset was considered, iEMG of medial gastrocnemius (p = .021) and lateral gastrocnemius (p = .004) were reduced during single-leg stance, when stimuli occurred between 300-450 ms prior to this phase. Participants committed more errors and had longer RT on the HARD task. RT was longer when subtracting while walking in comparison to subtracting alone. Young adults expressed dual-task cost in the motor and the cognitive tasks, suggesting that walking requires attention. There was a specific moment (300 ms after stimulus onset) during single-leg stance that dual-task cost occurred. Reasons for this interference and the implications of a reduction in iEMG while walking and performing an attention demanding cognitive task are discussed.


identifier: Bitar, Dory  (2007) Modeling and analysis of reinforced granular layer overlaying very soft soil.  PhD thesis, Concordia University.

abstract: Many regions of lowlands contain areas of very soft soils where large settlements are observed. Placing a fill over these areas will lead to extensive differential settlements. For this reason, reclaiming such surfaces with the aid of reinforcements is very essential.  The proposed model is an elastic-plastic constitutive model derived from CANAsand model which uses a non-associated flow rule along with the concept of the state boundary surface possessing the critical and the compact state. The model is capable of simulating the surface profile of reinforced granular fill over very soft soil due to the immediate settlement. A primary ground deformation profile is evaluated prior to filling and is based on a parametric study involving variables such as the height and the spacing of the embankment fingers, the stiffness modulus of the reinforcement and the cohesion of the soft soil. The numerical results indicated that these parameters affect the performance of the system in many direct ways. The immediate and final settlement is based on the level the first deformation has attained and is estimated using a nonlinear and incremental stress-strain analysis. An integro-differential equation written in its finite difference form is developed to estimate the total displacement field of the system. The computer generated results showed that larger surface settlements were associated with high void ratios whereas smaller surface settlements were associated with low void ratios.


identifier: Lavoie, Marie-Claude  (2007) Enabling contextual mLearning : design recommendations for a context-appropriate user interface enabling mobile learning.  Masters thesis, Concordia University.

abstract: The aim of this thesis is to provide design recommendations for a context-appropriate user interface enabling mobile learning (mLearning). mLearning applications are being used on mobile devices in classrooms with students of all ages.  How can the technology be merged within a device's operating system to help manage various phone events in order to aid in the management of learning activities. Participatory design was used and both qualitative and quantitative data was collected. Two interviews of 17 conveniently selected adult participants were performed which discuss time management strategies and specific uses of various technologies on mobile phones with participants.  I conclude that a mobile learning prototype should (1) be able to collect information autonomously; (2) should have a variety of functionalities; (3) should have modular functionalities in order to allow the user to customize the device; and (4) should have an interface as flexible as possible to cater to a variety of users


identifier: Hamzeh, Mona  (2007) Evolutionary genetic analyses of the forest tree genus Populus.  PhD thesis, Concordia University.

abstract: Populus , a genus of deciduous trees distributed throughout the northern-hemisphere comprising aspens, poplars and cottonwoods, has recently become a model for forest trees and subject of many interdisciplinary studies in higher plants. However, due to a high level of morphological diversity, extensive inter-species hybridization, and a low level of DNA sequence variation among species in this group, the taxonomy and phylogeny of the genus still remains controversial and incongruent phylogenetic relationships among poplar species have challenged evolutionary biologists for more than a decade.  Nuclear genomic data based upon inter simple sequence repeat (ISSR) as well as six nuclear genome based Sequence Characterized Inter Simple Sequence Repeat (SCISSR) data were used to assess genetic relationships among species of the genus Populus . The direction of natural hybridization between two sympatric Populus species in North America ( P. deltoides and P. balsamifera ) was also investigated using species-specific single nucleotide polymorphism (SNP) markers in both the nuclear and chloroplast genomes.  Overall, the genetic relatedness estimates based on nuclear ISSR data were congruent with phylogenetic trees based on other molecular (RFLP and DNA sequence) and morphological data, but provided better resolution in assessing the genetic relatedness among closely related taxa, and provided genetic evidence for previously suspected introgressions. The resulting SCISSR based tree was also mainly congruent with the genetic relatedness estimates based on other molecular (RFLP, ISSR, and DNA sequence) and morphological data, but showed better resolution of the internal nodes. This result would suggest the need for larger sequence data sets for precise reconstruction of phylogenetic relationships among closely related species of Populus .  Although hybridization is generally considered to be symmetrical, with both hybridizing species being equally likely to be the male or female parent, several studies have demonstrated the presence of asymmetrical hybridization and introgression from one species to the other. All natural hybrid individuals, identified based on morphological traits, had nuclear alleles corresponding to both parental species, while the chloroplast genotypes showed similarity to P. deltoides , indicating asymmetrical hybridization with P. deltoides as the maternal and P. balsamifera as the paternal donor species. This observed asymmetrical hybridization may be attributable to cytonuclear interactions.


identifier: Zhao, Ying  (2008) Monolayer behavior of phenolic lipids : experimental and computational studies.  Masters thesis, Concordia University.

abstract: The monolayer and bilayer behavior of 1,2-dipalmitoylgalloylglycerol (DPGG 1 ) is thought to be governed by strong intermolecular hydrogen bonding. To probe this hypothesis, monolayers of DPGG and its analogs ( 2-5 ) with variation in the position and numbers of hydroxyl groups on the aromatic headgroup, and 6 , in which all the hydroxyl groups of 5 were replaces by methoxyl groups in order to disrupt the hydrogen bonds, were studied experimentally and computationally.  It was found that at 25°C, all phenolic lipids formed aggregates at the air/water interface even at very high molecular areas, which suggests strong interactions between the phenolic lipid headgroups. Moreover, isotherms of 2 showed a shift to larger molecular area compared to those of the other phenolic lipids. A para --OH group played an important role in the monolayer behavior of the phenolic lipids.  To rationalize the differences in the surface properties of the phenolic lipids that are caused by changing the substitution pattern on the aromatic headgroup, the interactions between small model phenolic esters in the gas phase was studied with density-functional theory. The carbonyl group involved configuration had the lowest total energy for all the phenolic lipid headgroup dimers. Aggregation of the phenolic lipid headgroups was energetically favorable. The preferred conformation of the full DPGG molecule had two non-interacting side chains, and in order to change into the conformation for the solid state monolayer, in which the two side chains were aligned, an energy barrier of about 5.5 kcal mol -1 needed to be overcome.


identifier: He, Guang Qing  (2008) Quantification of two Gestalt Laws using curve resconstruction.  Masters thesis, Concordia University.

abstract: Visual perception is the ability to interpret, process, and comprehend all the information received through the sense of sight by association with earlier experiences. Researchers have long struggled to explain what visual processing does to create what we actually see, and brought many theoretical approaches explaining how human beings see the world. The theoretical approaches of visual perception differ widely and their coverage ranges from early theories such as Gestalt theory to recent computational theory in the field of Artificial Intelligence. According to the characteristics of visual perception, human beings tend to classify the ambient environment objects into different categories described by various symbols or objects. Similar symbols or even quite dissimilar symbols may be perceived as belonging together or belonging to different groups according to people's judgment. It must follow certain rules when human beings set up relationships between those objects and symbols, and finally obtain the unambiguous perceptual results through the process of visual perception. To find out the mechanisms underlying these properties of visual perception, this present thesis conducts experiments on perception using curve reconstructions as test cases. The perception model developed through the experiment is implemented in a curve reconstruction algorithm. It is assumed that a good perception model will reconstruct curves in the same manner as human beings perceive them. In the present thesis, a series of methods from Design of Experiments (DOE), ANOVA and the multivariate nonlinear regression model are applied to investigate the relationships between the points and curves. The results show that our perception model conforms to the pattern human perceives the points.


identifier: Mohajerin, Nima  (2008) A top-down approach to answering queries using views.  Masters thesis, Concordia University.

abstract: The problem of answering queries using views is concerned with finding answers to a query using only answers to a set of views. In the context of data integration with LAV approach, this problem translates to finding maximally contained rewriting for a query using a set of views. When both query and views are in conjunctive form, rewritings generated by existing bottom-up algorithms in this context are generally expensive to evaluate. As a result, they often require costly post-processing to improve efficiency of computing the answer tuples.  In this dissertation, we propose a top-down approach to the rewriting problem of conjunctive queries. We first present a graph-based analysis of the problem and identify conditions that must be satisfied to ensure maximal containment of rewriting. We then present TreeWise, a novel algorithm that uses our top-down approach to efficiently generate maximally contained rewritings that are generally less expensive to evaluate. Our experiments confirm that TreeWise generally produces better quality rewritings, with a performance comparable to the most efficient of previously proposed algorithms


identifier: Robertson, Emily  (2007) Pushing the envelope : the evolution of mail art in Canada.  Masters thesis, Concordia University.

abstract: Mail art can be most basically defined as art that uses the postal system. The post is the support, comparable to the painter's canvas. The art produced within a mail art context is traditionally exchanged outside the museum setting. Since its making is a shared responsibility between artists and the post office, each piece of correspondence undergoes a series of manipulations, some of which are intended by the sender, and others which are the inadvertent results on the part of the postal system in printing or sorting. Today, participants in the mail art movement are known interchangeably as mail artists, correspondents and networkers.  Pushing the Envelope explores the mail art phenomenon, providing readers with a detailed investigation of its emergence and evolution in Canada. This thesis covers such topics as the historical roots of mail art, the development of mail art magazines and archives, the relationship between mail art and the institutions that exhibit and collect this art form, as well as the movement's recent branching out to incorporate aspects of self-help. Each chapter explores a different decade, from the 1950s to the present day. Mail art projects by Anna Banana, Henrik Drescher, General Idea, Image Bank, Sarah Jackson, Ray Johnson, Amy Lam, Ed Varney and Frank Warren illustrate how the production of mail art evolved over time.


identifier: Chen, Lei  (2008) Computer-assisted transformation of design documents from a natural language description to structured modeling languages.  Masters thesis, Concordia University.

abstract: In the present thesis, a novel approach is proposed to transform design documents described by a natural language into a structured modeling languages, particularly UML diagrams and FBS models. The transformation consists of two steps: (i) From natural language to an intermediate graphic language called Recursive Object Model (ROM). (ii) From a ROM diagram to a modeling language.  The ROM diagram corresponding to a text includes the main semantic information implied in the text by modeling the relations between the words in a text. Based on the semantics implied in the ROM diagram, a set of criteria is proposed to mine the semantic meaning of the original text corresponding to the ROM diagram. Once the semantic meaning of the design documents through their corresponding ROM diagram is captured, a set of mapping rules from the ROM diagram criteria to the modeling language elements is proposed. After that, a set of generation rules to explore the relationship between these elements is proposed to generate UML diagrams and FBS models based on a ROM diagram. A software prototype R2U is presented as a proof of concept for transforming ROM diagrams to UML diagrams. Another software prototype R2FBS is also presented as a proof of concept for transforming ROM diagrams to FBS models. Several case studies show that the proposed approach is feasible. The proposed approach can be applied to requirements modeling in various engineering fields such as software engineering, automotive engineering, and aerospace engineering. Future work is indicated at the end of the present thesis


identifier: Wan, Wei  (2008) Specifying and verifying communities of Web services using argumentative agents.  Masters thesis, Concordia University.

abstract: This thesis includes two main contributions: the first one is specifying the use of argumentative agents in the design and development of communities of Web services; the second is using a formal technique to verify communication protocols against given properties for these communities.  Web services that provide a similar functionality are gathered into a single community, independently of their origins, locations, and ways of doing. Associating Web services with argumentative agents that are able to persuade and negotiate with others organizes these Web services in a better way so that they can achieve the goals they set in an efficient way. A community is led by a master component, which is responsible among others for attracting new Web services to the community, retaining existing Web services in the community, and identifying the Web services in the community that will participate in composite scenarios. Besides FIPA-ACL, argumentative dialogue games are also used for agent interaction.  In this thesis, we use tableau-based model checking algorithm to verify our argumentative agent-base community of Web services negotiation protocol. This algorithm aims at verifying systems designed as a set of autonomous interacting agents. We provide the soundness, completeness, termination and complexity results.  We also simulate our specification with Jadex BDI programming language and implement our verification with a modified and enhanced version of CWB-NC model checker.  Keywords. Multi-agent systems, BDI agent architecture, model checking, agent oriented programming, FIPA-ACL, dialogue game, agent-based negotiation protocol, Jadex, CWB-NC.


identifier: Ayouby, Reem  (2008) Acculturation to the global culture, cultural identification, and the intention to adopt the internet.  Masters thesis, Concordia University.

abstract: This report documents a research study on the effects of the global culture and cultural identification on the intention to adopt the Internet. The results of the study indicate that acculturation to the global culture is related to the intention to adopt the Internet. The relationship was shown to be mediated by perceived ease of use, perceived usefulness and subjective norm in two samples from two cultural communities. When the samples are combined, the relationship between acculturation to the global culture and the intention to adopt the Internet also becomes direct.  The model studied includes cultural identification in the form of two different constructs. One of the constructs is ethnic cultural identification and the other is national cultural identification. Ethnic identification has a significant positive relationship with subjective norm in only one case; otherwise these cultural identification concepts appear to be unrelated to the intention to adopt the Internet. This is contrary to prior research (Cleveland, 2006).  The study finds that cultural constructs, especially acculturation to the global culture, are important in starting to determine the antecedents of subjective norm in the IS field


identifier: Jean-Ruel, Émilie  (2008) The effect of ethical attributes on brand personality and consumer-brand relationships.  Masters thesis, Concordia University.

abstract: This research examines the effect of ethical attributes on brand personality and consumer-brand relationships--two rich marketing concepts, developed by Aaker (1997) and Fournier (1998), that have been investigated surprisingly very little to date. Specifically, it is hypothesized that: (1) ethical attributes can increase the sincerity and competence dimensions of brand personality (Aaker 1997); and (2) these personality dimensions can in turn favor the formation of strong and meaningful consumer-brand relationships such as committed partnerships, best friendships, and compartmentalized friendships (Fournier 1998). An experiment involving pairs of "ethical" and "mainstream" brands (e.g., The Body Shop and L'Oréal) was conducted to test these hypotheses. Results show that although both the sincerity and competence dimensions of brand personality can be increased by ethical attributes, only the competence dimension plays a significant role in shaping strong consumer-brand relationships. The results also suggest that the relationship between the competence dimension of brand personality and consumer-brand relationship strength is mediated by socio-emotional rewards. This research contributes to our understanding of the ability of marketers to manage specific dimensions of brand personality in order to elicit favorable consumer responses. Moreover, it allows marketing researchers and practitioners to better appreciate the phenomenon of ethical consumption, which is of increasing importance to today's firms.


identifier: Deichman, Alexander  (2007) P2P framework : a process and a supporting tool for deriving a conceptual design from user experiences.  Masters thesis, Concordia University.

abstract: Currently proposed User-Centered Design (UCD) artefacts such as patterns and personas lack commonly defined standards and tight integration into the design process. This is particularly important in the case of rapidly evolving industrial projects where high pressure from the market competes with the usability objectives. As a result, final design is often based on expert experiences without any ability to trace back the decisions.  We propose a UI design process and supporting software tightly integrating both artefacts with a goal to produce a conceptual design from user experiences. The proposed process consists of three phases: Persona Creating, Pattern Selection and Pattern Composition, resulting in representative persona set, ordered list of suggested patterns for each persona and a conceptual design respectively. On the other hand, the proposed tool supports the first two phases of the process by providing various automation algorithms for user grouping and pattern selection combined with the benefit of rapid pattern and user information access. Presented persona and pattern formats are augmented with a set of discrete domain variables to facilitate automation and provide an alternative view on the information.  Finally, the tool and the method are evaluated in the scope of a study on a bio-informatics tool. The results of the study are presented demonstrating a significant improvement in usability measures


identifier: Dascalescu, Diana  (2008) [alpha]-Olefins Coordination Polymerization studies with single site catalysts.  Masters thesis, Concordia University.

abstract: Due to their unusual physical properties, perfluorocarbon (PFC) solvents have found applications as immiscible reaction medium when unstable reagents are to be used. We became interested in using a fluorous biphasic system (FBS) for the metallocene-based polymerization of [alpha]-olefins. Here we present a study on its potential influences on the coordination polymerization mechanism and physical properties of the polymers synthesized in such conditions.  The first step of our study consisted of the design and set-up of a new polymerization reactor. Using zirconocene and methylaluminoxane (MAO), as catalytic system, preliminary tests of ethylene polymerization were carried out in order to test the system and assess process stability through the evaluation of ethylene polymerization yields and catalyst efficiency parameters (e.g., activity, turn over number, turn over frequency).  Catalyst efficiency parameters were all correlated, suggesting that the presence of a PFC in the reaction medium had a limited influence on the catalyst efficiency with little impact on the kinetics of the coordination polymerization process. When ethylene--1-hexene copolymerization reactions were performed in FBS, a negative comonomer effect was observed. Catalyst efficiency parameters calculated for FBS conditions were also affected by the presence of two monomers in the reaction medium.  Differential scanning calorimetry (DSC) was used to evaluate the melting temperature and the crystallinity of the synthesized polymers. The copolymers obtained in FBS were characterized by a relative higher proportion of amorphous structure compared to those synthesized in toluene only. The relative proportion of comonomer incorporated in the copolymers synthesized in FBS increased with increasing the 1-hexene concentrations.  Owing to their great potential, the study of FBS for Ü-olefin polymerization and copolymerization should be pursued until they find widespread application at the plant scale


identifier: Ding, Wu  (2008) Courtesy amount recognition using a feedback-based segmentation algorithm.  Masters thesis, Concordia University.

abstract: Paper checks play an important role in our modern commercial society. However, Reading paper checks and typing into computers manually is a time-consuming and labor-intensive task. Therefore, accurate and efficient Check Reading Systems (CRS) are in high demand by banks.  In this thesis, a CENPARMI CRS is introduced. Its courtesy amount recognition module is then presented in depth. The module makes use of a new feedback-based segmentation algorithm. The original segmentation algorithm can segment the inputted numeral string only once. The new algorithm can adjust the parameters of the segmentation algorithm according to the feedback information from the digit recognizer and can re-segment the inputted numeral string multiple times if necessary.  Two rejection strategies in the new segmentation algorithm are also presented. The first strategy is used for rejecting unreasonable segmentations, which can be accepted by the individual digit recognizer. The second strategy is used to avoid accepting a digit string as one digit.  Moreover, three algorithms in pre-processing and post-processing modules are proposed: a new border noise removal algorithm, an extra punctuations removal algorithm, and an implicit decimal points detection algorithm.  Finally, a Convolutional Neural Network (CNN) recognizer is integrated into the CRS to recognize "00" and "000" directly in order to avoid segmenting "00" and "000".  The experiment, based on the Bell Quebec check database, has shown that the courtesy amount recognition rate of the CRS has improved from 41.2% to 74.3%. The CRS can produce preliminary courtesy amount recognition results, which can be used for validation with the legal amounts to suppress the substitution rate.


identifier: Tang, Kai  (2008) Hydrophobic mismatch influencing the structure-function relationship of the reaction center from photosynthetic bacterium Rhodobacter sphaeroides.  Masters thesis, Concordia University.

abstract: The photosynthetic organisms consist a cluster of membrane bound protein-pigment complexes, which utilize absorbed photons to drive electron transfer reactions to convert light energy into chemical energy. In the photosynthetic bacterial reaction center from Rhodobacter sphaeroides , light induces a transfer of an electron from the primary electron donor, a special pair of two bacteriochorophylls forming a dimer, through a series of intermediate electron acceptors and a primary quinone Q A , to a reversibly-bound quinone Q B . Reaction centers from Rhodobacter sphaeroides have been reconstituted into various liposomes, with varying fatty acid chain lengths from C 12 to C 18 , resulting in different hydrophobic thicknesses of the lipid bilayer. Compensations are expected both from the lipid and the protein if the hydrophobic thicknesses are not matched. Lipid-protein interactions were explored and identified due to this hydrophobic mismatch by studying the phase behavior of the lipid and probing the function of the protein. The optimal thickness for the membrane, using saturated phospholipids to incorporate the bacterial reaction center, was found to be equivalent to a carbon length of C 14 . Prolonged illumination induced conformational rearrangements in the protein structure. Lipid environment, acidic pH, long illumination, and low temperature favored the formation of the long-lived charge separated state. This light-adapted conformation had a lifetime up to 8.9 hours, which is three million times as much as the lifetime of the dark-adapted charge separated state induced by flash excitations.


identifier: Ghanbari, Hamoun  (2008) A hybrid query engine for the structural analysis of Java and AspectJ programs.  Masters thesis, Concordia University.

abstract: Query-based code browsers can be customized to render many different types of views on-demand. In contrast to single-purpose browsers offered by modern IDEs such as Eclipse (e.g. Call Hierarchy), they release developers from mentally inducting the integral information from several views generated for specific purposes. However, customizing query-based tools, and communicating with their interfaces demands database expertise and understanding of the query language syntax. This puts a burden on maintainers by forcing them to encode their required views using complex queries. In this dissertation we investigate a query engine designed for software structural analysis which (1) provides a visual query interface over the high-level textual query language to eliminate the need for understanding the query language syntax, (2) incorporates the knowledge of programming language constructs into the factbase, query language, and the views, and (3) integrates the query-based and specific-purpose views already provided through the IDE. We are confident that this approach will be beneficial to maintainers during comprehension by allowing to abstract source code to high-level views and to speed up the rummage of the source code.


identifier: Katragadda, Rahul  (2008) Efficient heuristic for multicasting in arbitrary networks.  Masters thesis, Concordia University.

abstract: Multicast is a communication model in which a message is sent from a source to an arbitrary number of distinct destinations. Two main parameters that are used to evaluate multicast routing are the time it takes to deliver the message to all destinations and the traffic, i.e., the total number of links involved in the multicast process. It has been proved that finding an optimal multicast solution on both time and traffic is NP-hard. We propose a heuristic for the multicasting problem in an arbitrary network. We perform extensive simulations to test our heuristic for pure random network topology and two types of N-Level Hierarchical topologies.


identifier: Moradian, Talin  (2008) Near optimal shared-tree based multicasting in mesh networks.  Masters thesis, Concordia University.

abstract: Multicasting is an efficient information dissemination for a subscribed user group on networks. In this thesis the problem of multicasting in mesh-connected networks is studied. Having a group of processors distributed on mesh, the goal is to present a routing strategy such that every member of the group can effectively transmit data to the other members. The conventional strategies in solving the problem are source-based and shared-tree approaches, each having drawbacks in efficiency or scalability for large networks. To compromise between these two, we use the multi-shared trees approach. We apply a core-selection algorithm based on taxicab geometry to create a small number of distribution trees that are almost optimum with respect to multicast time and traffic.


identifier: Pourteymour, Amir Hossein  (2008) Implementation and comprehensive study of demand migration systems in Gipsy.  Masters thesis, Concordia University.

abstract: Intensional programming is a programming language paradigm based on the notion of declarative programming where the declarations are evaluated in an inherent multidimensional context space. Program identifiers are evaluated in a context, where each demand is generated, propagated, computed, and stored as an identifier-context pair.  General Intensional Programming System (GIPSY) is a hybrid multi-language programming system that overcame the limitation of previous Intensional Programming systems by designing a Demand Migration Framework (DMF) to provide a generic, dynamic, and technology-independent infrastructure.  A DMF instance, called a Demand Migration System (DMS), is used to propagate demands from one GIPSY execution node to another. A GIPSY program is executed using three components, each of which possibly having several instances, all of which possibly being executed on different nodes: the Demand Generator (DG), that generates demands according to the compiled Lucid program, the Demand Worker (DW), that executes procedure calls embedded in the Lucid program, and the DMS, that acts as a communication/storage middleware between the latter.  This thesis extends the previous investigations on the DMF by applying and extending DMF rationales and design to implement an instance of our DMS using Java Message Service (JMS-DMS).  JMS-DMS is an investigation toward having the combination of two paradigms of Message-Oriented Middleware (MOM) and Event-Driven Architecture (EDA) to handle our demand-driven computation. We also investigate on the behavior of our instances in different perspectives such as latency, dispatching, availability, scalability, maintainability, and configurability, which complements our research toward having the robust Demand Migration System.


identifier: Qiong, Huang  (2008) Extending magic sets techniques to deductive databases with uncertainty.  Masters thesis, Concordia University.

abstract: With the magic sets techniques having been proposed to improve the efficiency of bottom-up evaluations of Datalog programs by taking advantage of goal structure, we extend these techniques to deductive databases with uncertainty in the context of the parametric framework (PF). In our endeavor, we develop the generalized magic sets and generalized supplementary magic sets techniques, and establish their correctness. We have implemented the proposed techniques and have conducted numerous experiments for the assessment of the evaluation performance. Our experiment results reveal that different programs enjoy different efficiency gain, depending on the potential facts ratio, which measures the capacity to improve efficiency. When this ratio ranges from 1% to 20%, the efficiency observed was approximately 1 to 700 times faster. Our results also indicate that an integration of magic sets techniques and semi-naive evaluation with predicate partitioning yield the best performance.


identifier: Rohatgi, Abhishek  (2008) An approach towards feature location based on impact analysis.  Masters thesis, Concordia University.

abstract: System evolution depends greatly on the ability of a maintainer to locate these parts of the source code that implement specific features. Until recently, quite a number of feature location techniques have been proposed. These techniques suffer from a number of limitations. They either require exercising several features of the system, or rely heavily on domain experts to guide the feature location process.  In this thesis, we present a novel approach for feature location that combines static and dynamic analysis techniques. An execution trace is generated by exercising the feature under study (dynamic analysis). A component dependency graph (static analysis) is used to rank the components invoked in the trace according to their relevance to the feature. Our ranking technique is based on the impact of a component modification on the rest of the system. We hypothesize that the smaller the impart of a component modification, the more likely it is that this component is specific to the feature. The proposed approach is automatic to a large extent relieving the user from any decision that would otherwise require extensive knowledge of the system.  We present a case study involving features from two software systems to evaluate the applicability and effectiveness of our approach.


identifier: Seresht, Shadi Moradi  (2008) A methodology for semi-automatic assistance in elicitation and analysis of textual user requirements.  Masters thesis, Concordia University.

abstract: Requirements Engineering (RE) is a sub-discipline within Software Engineering increasingly recognized as a critical component in the success of a software development project. With the escalating complexity of software requirements, problems of traditional requirements engineering techniques, including the use of natural language text, are becoming increasingly apparent.  This research aims to assist software analysts in dealing with the challenges that exist in correctly understanding user requirements during the interactive process of requirement elicitation and analysis. It proposes a methodology related to visualization of textual requirements and was of making them shared, reviewed and debated by the stakeholders. The proposed methodology serves as a basis for a semi-automated process aimed at capturing the conceptual model of the software system under development and its high-level services from user requirements text. The extracted information can be used by analysts in their in-depth study of the requirements text and in avoiding the risks associated with specifying poor or invalid requirements.  The approach is based on a syntactic analysis and formalization of the text written in natural language and enriched with domain-related information extracted from reusable domain-specific data models. The applicability of this research is illustrated with a case study. A prototype implementing our methodology is developed as a proof-of-concept. The results of controlled experiments designed to evaluate our approach prove the validity of the methodology. The thesis discusses future work, issues, problems, and priorities. Furthermore, it proposes recommendations for textual requirements comprehension research


identifier: Carver, Tamara  (2008) Relation between physical exertion and postural stability in hemiparetic participants secondary to stroke.  Masters thesis, Concordia University.

abstract: Balance impairment secondary to stroke is an important issue to consider since it significantly increases the risk of falling and can lead to pathological events. The purpose of this study was to determine the effects of physical exertion induced by walking on postural stability in hemiparetic stroke participants. Twelve hemiparetic participants and 12 control participants walked over-ground for a duration of 6 minutes and 18 minutes at their comfortable speed. The control participants walked at a speed that allowed them to maintain the heart rate of their hemiparetic counterpart. Postural stability was measured during double-legged stance, sit-to-stand, and step reaction time tasks before the walk, immediately after the walk, 15 minutes post-walk, and 30 minutes post-walk. Measures of physical exertion during walking were also obtained from cardiorespiratory parameters, time-distance parameters, and subjective scales. The results indicated that physical exertion measures significantly increased when the duration of walk was increased from 6 minutes to 18 minutes in both control and hemiparetic participants. For postural stability measures, increasing the duration of walking led to a significant increase (p<0.05) of postural sway in double-legged stance and sit-to-stand for the hemiparetic participants only. This effect on balance of hemiparetic participants was observed immediately after the end of the walk. In conclusion, this study demonstrated that physical exertion can increase postural sway in hemiparetic participants which could possibly lead to an increased risk of falling in these individuals.


identifier: Shaikh, Ali Asghar  (2008) Efficient provisioning of passive optical networks.  Masters thesis, Concordia University.

abstract: Passive Optical Networks (PONs) have evolved to provide much higher bandwidth in access networks. They involve low cost equipment, fiber infrastructure, maintenance, and appear to be one of the best candidates for a major component of the next-generation access networks. A PON is capable of delivering bundled voice, data, video and other multimedia services. It is a point-to-multipoint optical network, where an optical line terminal, located at the central office, is connected to multiple ONUs through some intermediate nodes equipped with either optical splitters or array waveguide gratings. In this thesis, we have focused on PONs with splitters only and have developed different optimization models for multicasting and wavelength assignment, i.e., for efficient provisioning of PONs. We consider two different objectives: Maximizing the weighted number of granted requests and maximizing the weighted number of served ONUs under the condition of a limited number of wavelengths. Variants include combinations of the two objectives in order to capture a cost/revenue concern through appropriate definitions of the weights. We developed different models dealing with either a tree or a light mesh topology as well as with traffic-grooming, i.e., Time Division Multiple Access ( TDMA) or without traffic-grooming. Models correspond to integer linear programs and for some of them, we have favored a column generation modeling in order to solve the linear programming relaxation and obtain a scalable solution process. Simulations have been conducted to validate all the models (with/with traffic-grooming). We have also evaluated the performance of the traffic-grooming models to observe the grade of service in terms of the number of served ONUs, bandwidth, bandwidth usage/waste, as well as efficient provisioning of PONs, under three different traffic scenarios for the objective of maximizing the weighted number of ONU s.


identifier: Yao, Yuan  (2008) What could be happening in the frog's eye.  Masters thesis, Concordia University.

abstract: Our topic comes out of a juxtaposition of two classic papers: the 1943 paper A logical calculus of the ideas immanent in nervous activity by McCulloch and Pitts and the 1959 paper What the frog's eye tells the frog's brain by Lettvin, Maturana, McCulloch, and Pitts.  The nervous system is made up of individual signaling elements, the neurons. McCulloch and Pitts proposed a simplified model of this system. There every neuron receives a number of signals, which are nonnegative real numbers, at time t ; if a weighted sum of these signals exceeds a prescribed threshold, then the neuron sends signal 1 to other neurons at time t + 1; else it sends signal 0.  Lettvin et al. discovered that the frog's optical nerve transmits to the brain information obtained by preprocessing the data in the retina by four separate operations: sustained contrast detection, net convexity detection, moving edge detection, and net dimming detection.  We speculate about McCulloch-Pitts networks that could implement the fourth of these operations, the detection of sudden dimming. To be biologically plausible, such networks must conform to what is known about frog's anatomy: its retina consists one million photoreceptors, three to four million other neurons, every neuron receives signals from fewer than 100,000 neurons, and it sends signals to fewer than 10,000 neurons.  We construct such networks that, within a narrow margin of error, detect dimming from time t to t + 1 and respond at time t + 4.


identifier: Chou, Hsin-I  (2008) The role of APC activators Cdc20p and Cdh1p in regulating mitosis and morphogenesis in C. albicans.  Masters thesis, Concordia University.

abstract: Candida albicans is an important fungal pathogen of humans, and its ability to switch between different cell morphologies, including yeast, pseudohyphae and hyphae, is critical for virulence. The cell cycle plays an important, yet poorly understood, role in regulating cellular morphogenesis. Our previous work demonstrated that blocking the yeast cell cycle in mitosis, through depletion of the polo-like kinase Cdc5p, resulted in polarized growth of the yeast bud, producing filamentous cells that were distinct from pseudohyphae or true hyphae. Polarized growth was partially dependent on the spindle checkpoint factor Bub2p, suggesting that checkpoint-activated growth occurs in C. albicans . In contrast, similar checkpoint activation leads to cessation of cell proliferation in most other systems. In order to elucidate how mitotic progression and spindle checkpoints are linked to morphogenesis, a better understanding of the basic regulation of mitosis is required. To this end, we characterized homologues of Cdc20p and Cdh1p, which are targets of the spindle checkpoint and activators of the ubiquitin ligase anaphase-promoting complex (APC), a major regulator of mitotic progression in most systems. Cdc20p and Cdh1p were important for the metaphase-to-anaphase transition and mitotic exit, similar to their counterparts in S. cerevisiae , but strongly influenced morphogenesis in a different manner. Deletion of CDH1 resulted in a pleiotropic phenotype, including some enlarged yeast cells, while absence of the same factor in S. cerevisiae produced small cells. Absence of Cdc20p produced highly polarized yeast buds that resembled Cdc5p-depleted cells, in contrast to the large doublets resulting from loss of Cdc20p in S. cerevisiae . Overexpression of CDC20 in Cdc5p-depleted cells partially suppressed the cell cycle defect, suggesting that Cdc20p may be downstream of Cdc5p. However, polarized growth was not abolished. Deletion of the putative Cdc20p-binding and spindle checkpoint factor Mad2p partially compromised polarized growth in Cdc5p-depleted cells, implying that Mad2p may play a role in linking Cdc5p function with Cdc20p. Deletion of CDH1 had no effect on Cdc5p-dependent polarization, suggesting that Cdh1p is dispensible for the process. While Cdc20p was not required for serum-induced hyphal growth, some cells lacking Cdh1p were not able to form hyphae, yet invaded agar more readily than control cells, suggesting a complex role for this factor in regulating polarized growth. Thus, we provide genetic evidence that Cdc20p and Cdh1p play important roles in regulating mitosis and morphogenesis in C. albicans , but in a different manner than their homologues in S. cerevisiae . Our results extend our knowledge of the regulatory circuit governing mitosis in C. albicans and the potential pathway underlying checkpoint-activated polarized growth.