Information modeling is the cornerstone of information systems analysis and design. Information models not only provide the abstractions required to facilitate communication between designers and end users, they also provide a formal basis for tools and techniques used in developing and using information systems. This dissertation reports on four empirical studies in information modeling. The four studies focus on an important, yet controversial, construct in information modeling — the relationship construct. The theoretical foundation for the four experimental studies comprises theories and findings from the information systems, cognitive psychology, computer science, philosophy, and communication literature. Because of the paucity of empirical research in the area, a two-stage research design, consisting of the exploratory and formalized phases, is employed in this dissertation. Two studies were conducted in the exploratory phase. The first exploratory study investigated the effect of domain familiarity on selection of mandatory or optional connectivity for the relationship construct by modeling experts. The findings indicate that modeling experts tend to choose optional over mandatory relationships, even for domains that are totally unfamiliar to them. The second exploratory study analyzed the effect of conflicting textual information and structural constraints on selection of mandatory or optional connectivity by modeling experts. The results show that modeling experts tend to focus on the information depicted by the structural constraints and ignore the textual information. This exploratory phase allowed us to explore and develop empirical research methods and instruments for studying the relationship construct in information modeling. In the second phase, two formalized studies were conducted. The first formalized study investigated the differences between modeling experts and novices in their interpretation of information models. The results show significant differences in the way modeling experts and novices interpret information models. Modeling experts focus mainly on the structural constraints and de-emphasize the textual information. Modeling novices, on the other hand, pay more attention to the textual information than modeling experts. The second formalized study examined the effect of different representations of relationship on the interpretation of information models by modeling novices. The findings indicate that the explicitness of relationship construct and the use of verb versus noun description for relationship have a profound impact on the accuracy of interpretation. The best combination is one that uses an explicit relationship construct and verb for relationship description. The worst combination is one where the relationship construct is represented implicitly and described using noun. / Business, Sauder School of / Graduate

Situated between the casting and rolling operations, the reheating process ensures steel billets or slabs are at temperatures high enough (~1200°C) to enable subsequent deformation pro-cesses to be carried out economically. Industrial reheating furnaces have varying designs, utilize different fuel mixtures and employ top, side or bottom firing. Under steady-state operating cond-itions, the challenge is to achieve good temperature homogenization while minimizing fuel con-sumption and maximising furnace throughput. During furnace stoppages, which are caused by delays in therolling mill, there is a need to minimise fuel consumption and maintain discharge temperatures. To gain better insight into the operation of a billet reheating furnace, a transient, three-dimen-sional thermal model has been developed. Radiative heat transfer in three-dimensions is solved using Hottel's "Zone Method", employing a clear-plus-three-grey gas model to represent the furnace atmosphere. In this method, the geometrical aspects of the problem are treated sepa-rately to produce total exchange areas that can be stored for repeated use. The main module then calculates the energy released through combustion, the heat transferred to the steel and the move-ment of the charge during each time step. Gas temperatures are determined from energy balances using a Newton-Raphson iterative technique. Conduction in the billets is solved in three-dimensions by taking into account heat transfer in the gaps between and underneath the billets. The model further evaluates heat losses through the furnace roof, walls and hearth. The mathematical model was verified using industrial data obtained from plant trials con-ducted at two Canadian steel mini-mills. Results from the plant trials indicated that the billets con-tinued to increase in temperature during furnace stoppages. The model suggests that this is due to continuous burner firing during these stoppages even with lower firing levels. For one of the furnaces, the model predicts the thermal efficiency to be 31% for the heating of 0.15 m (6") billets, with 68% of the combustion energy lost in the flue gases and the remainder lost through the refractory. Improved performance could be realized through better control of the furnace atom-sphere, with the air/fuel ratios maintained at levels closer to stoichiometric, as well as the installa- tion of a recuperator to preheat the combustion air. Different delay firing strategies that focussed on the recovery of the furnace were examined with the model and it was found that the sequential return to steady-state firing reduces the extent of billet over-heating while ensuring newly charged billets reached adequate rolling temperatures. The model was also used to examine the effect of air/fuel ratios in each of the furnace control zones and the benefits of recuperatively preheating the combustion air or hot-charging, where the billets are charged into the furnace soon after casting. / Applied Science, Faculty of / Materials Engineering, Department of / Graduate

The measurement of neurotransmitter secretions by living cells, both in living organisms or in preparations, constitutes an enduring and vexing problem for neuroscientists due to the large number of substances involved at very low concentrations. An ability to correlate neurotransmitter secretions with various factors including organismic behavior would greatly advance our understanding of the organization and functioning of central nervous systems. This, in turn, has many important implications for the diagnosis and treatment of disorders of central nervous systems (mainly in humans) as well as for the design and implementation of information processing and control systems. The work presented here was undertaken in order to explore a novel approach to this demanding problem. The objective was to develop a probe capable of measuring neurotransmitter secretions in real time, at physiologically relevant concentrations, and non-invasively in situ. Data were obtained using an ultraviolet resonance Raman spectroscopic analytical technique performed via optical fibers, and were analyzed primarily with artificial neural networks. To this end, a prototype tunable ultraviolet resonance Raman system was designed, assembled, comissioned and employed. A general introduction to the problem and a discussion of existing techniques for neurotranmitter measurement are given in Part I. In Part n, the analytical method was shown to allow discrimination between several different neurotransmitters and some of their precursors, both on the basis of their spectra and the selective resonance enhancement of their spectra. Optical fibers were characterized with regard to their suitability for use with pulsed ultraviolet radiation in Part III and on the basis thereof selected for the construction of optical fiber probes. It was found that the performance of optical fibers varied greatly when subjected to pulsed ultraviolet radiation, making the selection of fibers a crucial factor in probe construction. Various design features influencing the efficiency of optical fiber probes were investigated using both theoretical and empirical techniques. A right-angle geometry using a small diameter excitation fiber and several larger collection fibers in close proximity produced the most efficient probe. In Part IV the use of cell secretions as samples modelling in vivo conditions were investigated. It was also shown that these probes could be inserted via surgically implanted cannulae into and operated in the crania of experimental male rats without producing discernable behavioral artifacts. In Part V some signal recovery methods were investigated and it was shown that artificial neural networks could be used to identify and quantify neurotransmitters based on their Raman spectra. Part VI contains an assessment of the neuroprobe using neurotransmitter secreting cultured cells as a model system. The thesis is concluded with a discussion of the charateristics of an ideal biosensor, reviews the work done, and highlights some future directions. This thesis represents my contributions toward the development of a tunable ultraviolet resonance Raman neurotransmitter probe. Within the scope of this work, limitations of the available equipment and other resources precluded the complete development of a high-performance neuroprobe, however, the data presented here demonstrate proof-of-concept and feasibility. In particular, what has hitherto been considered impossible - the use of optical fibers for pulsed ultraviolet remote resonance Raman spectroscopy - has been shown to be distinctly feasible. It has further been shown that ultraviolet resonance Raman spectroscopy is well-suited to the problem of resolving a mixture of neurotransmitters in a biological matrix. With the appropriate state-of-the-art equipment, there is now a very real possibilty of obtaining detection limits of lx10~9 M for the catecholamine neurotransmitters and 1x10"0" M for the aliphatic neurotransmitters with 30 s exposure time, thus providing a novel and general solution to the problem of neurotransmitter measurement. / Graduate and Postdoctoral Studies / Graduate

This thesis argues the continued relationship between museums and the middle class over the period from 1850 to 1950, showing in particular how major events and trends affecting the history of the middle class influenced the manner in which museums developed. It argues, however, that, despite participation in an international bourgeois culture which included a worldwide "museum movement', the regional circumstances of both museums and the middle class in Canada had a significant effect on their related histories determining, if not the final product, at least the timing of its completion and the manner in which it was reached. This argument is made through a comparison of the histories of the Provincial Museum of Nova Scotia, the Ontario Provincial Museum, the Royal Ontario Museum, and the British Columbia Provincial Museum. For each institution, three themes are considered: the way in which its collection shaped or reflected a regional identity; the form of education it offered, the intended audience, and the ways in which both changed; and the impact of professionalization on both the museum and the people who worked in it. The comparisons show that, despite the uniqueness of the museums' collections and histories, in the final analysis, each institution conformed to the patterns of the 'museum movement', or, as in the case of professionalization, to the pattern of a professionalizing middle-class society. Informed by recent critical work on the history of museums, this thesis uses archival and secondary sources to establish the narratives of four Canadian museums and places them into the broader context of the international 'museum movement', while also indicating the uniqueness of Canadian cultural institutions created by the colonial experience. In this way, it adds a new perspective to the history of Canadian museums. At the same time, it adds to our understanding of the Canadian middle class through its demonstration of how the major societal trends affected individual members of that class. / Arts, Faculty of / History, Department of / Graduate

A fundamental study of the undrained behaviour of sands under multi-axial loading is presented. The study was performed by using the hollow cylinder torsional (HCT) device. The HCT is the only device that permits a soil specimen to be subjected to multi-axial loading with controlled variations in the magnitudes of the three principal stresses and the direction of the major principal stress with the vertical deposition direction. The main objective of the study was to assess the effects of principal stress magnitude, directions and their rotation on sand liquefaction. This is achieved by a systematic study of static and cyclic undrained behaviour of reconstituted loose sand. Shear loading is carried out under strain control. Only such loading permits the needed capture of post peak strain softening characteristics of loose sands. Undesirable runaway strains are inevitable in stress controlled loading modes. In addition to the investigations in the hollow cylinder torsional device, sand behaviour in simple shear as well as under the triaxial conditions was also assessed as reference for comparisons with that under multi-axial stresses. The investigations were carried out using two sands - Fraser River sand and Syncrude sand. Sand specimens were reconstituted by water pluviation, which is considered to duplicate the fabric ofin-situ fluvial and hydraulic fill deposits. Independence of the effective stress path and stress-strain characteristics from the total stress path under fixed principal stress directions and constant value of intermediate principal stress parameter is illustrated. The undrained response of loose sand is highly dependent on the loading direction, implying inherent anisotropy. The friction angle mobilized at phase transformation or steady state is a unique material property, independent of the mode of loading static or cyclic, direction of principal stresses, intermediate principal stress level, consolidation history and the stress and void ratio state prior to undrained shear. There is no unique relationship between steady state or phase transformation strength and void ratio that is independent of the stress path, implying that a unique steady state line does not exist for a sand. The influence of intermediate principal stress, on undrained response is small when the intermediate principal stress parameter, that reflects value of this stress relative to the major and the minor values, is less than about 0.5. At constant values of other parameters increasing confining stress and decreasing relative density under multi-axial loading promote a higher degree of contractive response. The history of principal stress directions during principal stress rotation does not seem to have any appreciable effect on the peak and steady state or phase transformation strength. These strengths are apparently controlled by the peak value of major principal stress inclination experienced during shearing with respect to vertical direction. Principal stresses undergo continuous rotation from 0 to about ±45° in simple shear deformation. A simultaneous change in intermediate principal stress occurs as the major principal stress rotates. The maximum shear stress and maximum shear strain in conventional simple shear deformation approximately equals the horizontal shear stress and shear strain respectively. For a given initial stress and void ratio state, the number of cycles to liquefaction is smaller under cyclic triaxial than under similar 90° jump rotation that do not invoke the weakest triaxial extension loading mode during shear. For a given direction of principal stresses, if the sand is contractive under static loading, it would also be contractive under cyclic loading, provided that the cyclic deviator stress amplitude is higher than the steady state or phase transformation strength in static loading. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

This research examines the planning of the Besters Camp informal settlement in-situ upgrading project in Durban, South Africa. International experience indicates that in-situ upgrading has generally been successful in delivering services to the urban poor. It also confirms, however, that benefits of upgrading are mostly confined to project localities, and that the institutional capacity necessary for ongoing improvement in the lives of settlement residents is seldom created. Drawing from experience as a planner in some of South Africa's first generation of settlement upgrading projects, this research focuses on the question of how informal settlement upgrading can be planned in order to contribute to the continuity of the settlement improvement process. An important implication of the 'informalization' process in many Third World cities is that parts of cities in which the de facto rules of the game are dominant are growing considerably more rapidly than the 'formal city', which is governed according to the de jure instruments of control, such as statutory law, planning regulation, and legal administrative authority. In this context, the most common approach to planning the upgrading of shack settlements is to attempt to legalize, or 'formalize the informal'. Experience in Besters Camp upgrade elucidates ways of moving beyond a narrow focus on legalization, and onto more flexible regularization strategies. These strategies attempt to bridge the gap between de jure and de facto systems by integrating elements of both into the planning process, and thereby contributing to an amended legal regulatory framework appropriate to planning in informal settlements. Regularization involves putting in place the institutions - that is, the norms and structures - that are economically and politically viable, and which have the potential to carry the consolidation process forward into the longer term. Regularization takes as its starting point the delivery of services, which provides an activity into which capacity building initiatives can be integrated. Importantly, in order to sustain the impacts of upgrading projects, it is necessary to connect local settlement-level institutions and metropolitan-level institutions in such a way as to provide a relationship of complementary autonomy at both levels. / Applied Science, Faculty of / Community and Regional Planning (SCARP), School of / Graduate

This thesis considers the management of groundwater pollution as a societal and technical problem. It consists of four elements: theoretical foundation, conceptual model, management strategies, and compound model. The theoretical foundation recognizes two distinct approaches to management: the hard and soft paradigms. The hard paradigm deals with hard problems, characterized by well-defined boundaries, goals, and alternatives; quantifiable uncertainty; and a unilateral decision-maker. A hard problem can be addressed with algorithmic logic and linear procedure. The hard paradigm employs condensed conceptual models, and relies on transform models as predictive tools. (A conceptual model synthesizes observations; a transform model maps an input to an output.) The soft paradigm deals with soft problems, characterized by ambiguous boundaries, goals, and alternatives; nonquantifiable uncertainty; and multiple decision-makers. A soft problem requires argumentation and iterative procedure. The soft paradigm relies on detailed conceptual models, and employs transform models as heuristic tools. The two paradigms can be reconciled through the concept of soft/hard complementarity which views a problem as a soft problem in the overall sense, with embedded hard sub-problems. The conceptual model contains two major systems: the pollution system, consisting of groundwater flow and pollutant transport subsystems; and the management system, consisting of technical and decision subsystems. The emphasis is on the decision subsystem, which is described in terms of rules of governance; multiple issues; multiple stakeholders; and various decision processes. The management strategies include both decision and technical strategies. The decision strategies consist of three subsets: strategies for iterative decision-making; strategies for integration of the decision system; and strategies for emphasizing negotiation. The technical strategies deal with iterative technique; integration of the technical system; and design for mitigation. The compound model is called SAM (Simulated Aquifer Management). It consists of a set of transform models, joined by linkages which are either algorithmic or which require the modeler's subjective judgement. The technical system is represented by models of flow, transport, optimization of pumping rates, and costing of technical options. The decision system is represented a game theory model and a role-playing exercise. SAM is used as a heuristic device, and as illustration of both the management strategies and soft/hard complementarity. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Experiments were carried out in three-phase fluidized beds containing solid particles contacted by upward co-current flow of air and water, to study flow patterns of gas-liquid-solid systems. The minimum fluidization velocity and the particle transport velocity in a gas-hquid-solid mixture delineate the boundaries between three types of flow systems — fixed bed, fluidized bed and transport flow. Both of these transition velocities were measured for a variety of particles. A theoretical model, the Gas-Perturbed Liquid Model, was developed to predict the minimum liquid fluidization velocity of a bed of solid particles in the presence of a fixed co-current superficial gas velocity. This model, together with an appropriate equation for the gas holdup on a solids-free basis, shows almost as good agreement with the present experimental data and those from the literature as the best available empirical equation for the minimum hquid fluidization velocity at low to intermediate superficial gas velocity, and has the advantage of correctly reducing to the Wen-Yu equation for minimum two-phase fluidization as the superficial gas velocity goes to zero. Two types of particle movement were observed as the superficial liquid velocity approaches the particle transport velocity. For 1.2 mm steel shot, clusters of particles were found in both liquidsolid and gas-hquid-solid systems. For 1.5 and 4.5 mm glass beads, on the other hand, no particle clusters were observed. In the latter case, a mathematical model the Particle Transport Velocity Model, was developed to predict the superficial hquid velocity for particle transport in upward gas-hquid flow. An empirical correlation was also proposed for the transition from fluidized bed to particle transport flow. Both predictions showed good agreement with experimental data obtained in the present work and in the literature for a wide range of superficial gas velocities. Within the fluidized bed, based on bubble characteristics, dispersed bubble flow, discrete bubble flow, coalesced bubble flow, slug flow, churn flow, bridging flow and annular flow regimes were identified and characterized, at different combinations of gas and liquid superficial velocities. These flow regimes were also observed for two-phase air-water systems. A comprehensive measurement method using a conductivity probe was developed to determine flow regime transitions based on bubble frequency, Sauter mean bubble chord length and the time taken by a bubble to pass a given point. Criteria for determining flow regime transitions were developed in an air-water two-phase system and then successfully applied to gasliquid- solid three-phase fluidized beds. Flow regime maps were derived based on experimental data for three different three-phase systems. As in two-phase gas-liquid systems, chum flow, bridging flow and annular flow can be observed at high gas velocities in three-phase fluidized beds. Empirical correlations were developed to predict the flow regime boundaries in the three phase fluidized systems investigated. / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate

In some sections of railroad, many prestressed concrete railway ties were found to be cracked after being in service for only a few months, because of impact loading. The dynamic properties of concrete ties were thus studied in this work. Two typical types of impulse encountered in track, due to rail abnormalities and "wheel flats" of trains, were successfully simulated by the use of a 578 kg impact machine and a 60 kg drop weight impact machine, respectively. The previously developed "single-blow" impact technique has been extended into a "multi-blow" impact technique, in order to better simulate the repeated impact loading on the concrete tie in track. It was found that the stiffness of the rubber support played an important role in the dynamic response of the ties. Using the soft rubber support caused a low maximum load, low loading rate, a higher fracture energy and a ductile flexural fracture mode. Using the hard support caused a brittle flexure-shear or shear failure mode. Crack mode analysis showed that the cause of the crack mode changing from flexural under quasi-static loading to shear under impact loading is that the shear to moment ratio at the mid-span of the tie changes under impact. A crack mode prediction method was proposed. In the second series of tests, twelve types of modified ties were tested. The effects of the concrete strength, steel fibre additions, changes in prestressing force, the presence of stirrups were examined. The crack opening length and residual crack length were detected by crack detection gauges. Steel fibres greatly improved tie behaviour, leading to shorter and finer cracks in the concrete. Stirrups can, particularly when used in conjunction with fibres, effectively retard the deterioration of the concrete tie. The ties with a 40 MPa compressive strength and 30 mm fibres behaved very well. They were markedly better than the ties which had the same fibre content but a 65 MPa concrete compressive strength. The reason for this is that reducing the concrete compressive strength or prestressing level of the tie resulted in a reduction of the dynamic flexural stiffness and hence the magnitude of the impact loads. It is believed that if these measures were combined with the use of steel fibres in the concrete, a new type of concrete tie, with improved ductility and high resistance to impact load could be developed. Dynamic analysis of the ties showed that a different impulse duration or frequency may lead to a very different concrete strain response. This may need to be considered in the wheel truing program in service. Thirteen types of commercial pads were tested and ranked. Soft pads may act as a low-pass filter, leading to lower amplitudes of the concrete strain vibration. However, it may structurally deteriorate more quickly, leading to an even worse influence on the ties after a period of time in service. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

The range of thermally stable, predominantly a-bonded metal carbonyl derivatives has been expanded to include Pd(I), Pd(II), Ir(III), Os(II), and Ru(II). The new compounds, [Pd(CO)₄][Sb₂F₁₁]₂, cis-Pd(CO)₂(SO₃F)₂, [Pd₂(µ-CO)₂](SO₃F)₂, [Pd₂(µ -CO) ₂][Sb₂₁₁]₂, mer- Ir(CO)₃(SO₃F)₃, [Ir(CO)₅Cl][Sb₂ F₁₁]₂, [Ru(CO)₆][Sb₂F₁₁]₂, [Os(CO)₆][Sb₂F₁₁]₂, and cis- Pt(CO)₂(Sb₂Fn)₂ have been synthesized. The compounds have been characterized using a variety of physico-chemical techniques: elemental analysis, FT-IR and Raman spectroscopy, and ¹³C NMR spectroscopy. For cis-Pd(CO)₂(SO₃F)₂, [Pd₂(µ-CO)₂](SO₃F)₂, mer- Ir(CO)₃(SO₃F)₃, and [Ir(CO)₅Cl][Sb₂F₁₁]₂, the molecular structures have been determined by single crystal X-ray diffraction. [More abstract follows; please see pp.3+ of the accompanying pdf file] / Science, Faculty of / Chemistry, Department of / Graduate