Atmospheric carbon monoxide (CO) is a product of incomplete combustion and a byproduct of the oxidation of hydrocarbons. It plays a key role in controlling the oxidative capacity of the atmosphere since it is the main sink for the hydroxyl radical (OH), the primary tropospheric oxidant. As a result of its lifetime, CO is a useful tracer of long-range transport in models. However, estimates of the regional sources of CO are uncertain. Inverse modeling has become a widely used approach for better quantifying the sources, but a fundamental assumption in these inversions, which is typically not valid, is that the observations and models are unbiased. In this thesis, the GEOS-Chem model and observations of CO from the Measurement Of Pollution In The Troposphere (MOPITT) instrument are employed to study the impact of systematic model errors on inversion analyses of CO. The impact of the treatment of biogenic non-methane volatile organic compounds (NMVOCs), aggregation errors, and discrepancies in the meteorological fields and OH distribution on the CO source estimates are examined. The influence of vertical transport errors on the source estimates is assessed using newly available MOPITT version 5 (V5) retrievals in a comparative inversion analysis employing surface level, profile, and column data. To quantify the potential impact of discrepancies in long-range transport on the source estimates, a high-resolution, regional inversion over North America, with optimized lateral boundary conditions, was conducted and compared with the results of a global inversion. The influence of the spatial-temporal distribution of the observations on the source estimates was also assessed through a comparison of the inversion analyses of MOPITT data and aircraft data from the Intercontinental Transport Experiment – North America, Phase A (INTEX-A) aircraft campaign. The results presented in the thesis provide a more comprehensive understanding of the potential impact of system model errors on inversion analyses of CO. This work also represents the first inverse modeling analysis of the MOPITT v5 retrievals. The results demonstrate the potential utility of these new data for characterizing vertical transport errors in models and they reveal that the new data can provide reliable constraints in regional CO source estimates.

Atmospheric carbon monoxide (CO) is a product of incomplete combustion and a byproduct of the oxidation of hydrocarbons. It plays a key role in controlling the oxidative capacity of the atmosphere since it is the main sink for the hydroxyl radical (OH), the primary tropospheric oxidant. As a result of its lifetime, CO is a useful tracer of long-range transport in models. However, estimates of the regional sources of CO are uncertain. Inverse modeling has become a widely used approach for better quantifying the sources, but a fundamental assumption in these inversions, which is typically not valid, is that the observations and models are unbiased. In this thesis, the GEOS-Chem model and observations of CO from the Measurement Of Pollution In The Troposphere (MOPITT) instrument are employed to study the impact of systematic model errors on inversion analyses of CO. The impact of the treatment of biogenic non-methane volatile organic compounds (NMVOCs), aggregation errors, and discrepancies in the meteorological fields and OH distribution on the CO source estimates are examined. The influence of vertical transport errors on the source estimates is assessed using newly available MOPITT version 5 (V5) retrievals in a comparative inversion analysis employing surface level, profile, and column data. To quantify the potential impact of discrepancies in long-range transport on the source estimates, a high-resolution, regional inversion over North America, with optimized lateral boundary conditions, was conducted and compared with the results of a global inversion. The influence of the spatial-temporal distribution of the observations on the source estimates was also assessed through a comparison of the inversion analyses of MOPITT data and aircraft data from the Intercontinental Transport Experiment – North America, Phase A (INTEX-A) aircraft campaign. The results presented in the thesis provide a more comprehensive understanding of the potential impact of system model errors on inversion analyses of CO. This work also represents the first inverse modeling analysis of the MOPITT v5 retrievals. The results demonstrate the potential utility of these new data for characterizing vertical transport errors in models and they reveal that the new data can provide reliable constraints in regional CO source estimates.

The key to the co-rotational (CR) finite element is the separation between the rigid body motion and the deformational motion. It is this separation which makes it superior to other methods in the analysis of large displacement problems. Since the dynamic analysis of a guyed transmission line system contains large displacements from the vibration of the cable, it is considered appropriate to utilize the technique in the analysis. This thesis re-formulates and simplifies the CR method for such a purpose. Numerical tests show that the time step required for convergence in the present technique is ten times less than that is required for convergence in ANSYS. In the construction of the equation for the prediction of the longitudinal load factor (LLF) for the A402-M guyed transmission line due to cable break events, the tower is modelled using a simplified model of a detailed lattice tower. The simplified model considers latticed tower segment as an equivalent beam segment. The use of the simplified model enables to perform the broken wire dynamic analysis of the ten-span transmission line system within a day or two on a personal computer. Two initiating events are considered: all conductors on one arm break and all cables in one span break. Based on the analysis results, it is found that the LLFs for the all cables break event for the A402-M tower are 5% less than that calculated using the EPRI equation. It is therefore recommended that either the LLFs derived from the EPRI equation or from the proposed equation be used in the design of a guyed transmission tower for the broken wire event. The developed procedure can also be used to predict the LLF for the other type transmission line systems.

De 2006 à 2010, nous avons étudié le cas d’une université québécoise ayant implanté Moodle, une plateforme en ligne d’apprentissage. Celle-ci permet aux enseignants de créer un espace personnalisé sur Internet destiné à diffuser des ressources numériques à leurs étudiants, à interagir avec ceux-ci et à les faire participer à des activités d’apprentissage. Alors que plusieurs études se sont déjà penchées sur le potentiel pédagogique de ce type de technologie, nous l’avons plutôt abordé en tant qu’outil de travail des enseignants, en nous intéressant à l’émergence d’un processus de co-configuration dans un contexte où l’organisation implante et supporte à l’interne une technologie open source. Contrairement aux méthodologies de design participatif ou de développement logiciel itératif qui se préoccupent de l’implication des usagers dans les phases antérieures de la conception, les pratiques de co-configuration que nous décrivons concernent un produit existant qu’on adapte localement après son implantation. L'accessibilité au code source de Moodle ainsi que les échanges mutuels entre les développeurs et les usagers permettent à l'organisation utilisatrice de personnaliser l’outil tout au long de sa durée de vie, et non seulement lors de périodes circonscrites de design et de conception. Les problèmes rencontrés par les enseignants constituent donc le point de départ temporel de leurs interactions avec les développeurs à l’interne. Les usages en contexte réel de travail révèlent à la fois certaines structures organisationnelles difficilement perceptibles aux développeurs avant l’implantation et rendent plus visibles les pratiques hétérogènes des enseignants. En accroissant la capacité d’action des développeurs, l’accès au code source du logiciel crée un contexte plus favorable à la prise en compte des demandes des usagers, puisque les développeurs peuvent « localiser » plus facilement les problèmes rencontrés en allant regarder comment le logiciel a été programmé et comment il pourrait être modifié pour mieux répondre à leurs besoins. Le caractère incrémental des modifications apportées localement à Moodle fait en sorte que les développeurs puissent accommoder certains besoins très spécifiques - voire uniques - tout en s’assurant de répondre aux besoins de la majorité, en plus d’assurer la compatibilité entre la version locale et la version officielle du logiciel. D'un point de vue conceptuel, nous avons mobilisé la théorie de l'activité en tant que cadre d’analyse (Engeström, 1987). La théorie de l’activité considère le changement comme un processus de résolution de contradictions, c’est-à-dire une séquence d’événements autour desquels s’articule la transformation des pratiques. Les différents niveaux de contradiction permettent de mieux saisir les liens entre les nouveaux patterns d’interaction et les pratiques institutionnalisées, de même que les implications des changements pour les systèmes d’activité voisins.

Epoxy resins are widely used as coatings, encapsulations, structural composites, castings, and adhesives in a number of electrical applications. Recently, novel uncatalyzed co-anhydride cured epoxy formulations that exhibit a high performance property profile, have been introduced. The objective of this thesis was to perform a comprehensive material characterization of these new resin/hardener combinations, which are potentially used as electrical insulation material in medium and high voltage engineering. The thermal cure behaviour of commercial tetraglycidyl-diamino-diphenylmethane (TGDDM) and a co-anhydride mixture consisting of maleic anhydride (MA) and hexahydrophthalic anhydride (HHPA) was extensively studied. Different analytical real-time methods, such as FT-Raman spectroscopy, differential scanning calorimetry, and chemo-rheological methods were applied to investigate the principal polymerization mechanism and the related curing kinetics. It was demonstrated that kinetic parameters that were based on isothermal measurements provided consistent and reliable results. On the other hand the general limitations of different dynamic methods for kinetic parameter calculations were outlined and discussed. Temperature modulated differential scanning calorimetry provided a powerful technique to confirm a TGDDM/MA and TGDDM/HHPA sub-network structure of the co-anhydride cured epoxy. A generalized time-temperature-transformation-diagram was developed in order to predict the complex material transformations (e.g. gelation and vitrification) occurring during the entire isothermal curing process. In the selected system, the mechanical deformation and fracture behaviour as a function of temperature, strain rate, inorganic filler fraction, particle size, and filler/matrix-adhesion were thoroughly studied by using compression-, tension- and double torsion fracture-tests. The potential of hyperbranched polymers (HBPs) as low viscosity toughening modifiers for highly crosslinked anhydride-cured epoxy networks was experimentally evaluated. The effects of the HBP molecular structure, in particular the specific shell chemistry, on thermo-mechanical properties, final morphology, and blend concentration, were assessed. For the neat investigated epoxy-system the most efficient toughening modifier was obtained for a molecular HBP-design that provided a pseudo-homogeneous blend morphology. Thus, by using suitable HBPs in a concentration of 20% w/w, the fracture toughness, expressed by the critical stress intensity factor (Klc) of 0.58 MPam(to the power of)0.5, was increased by over 50% to 0.88 MPam(to the power of)0.5. The corresponding Young's modulus and glass transition temperature were only affected to a limited extent by the addition of the HBP-additive. The toughest epoxy blend (critical stress intensity factor of about 1.6 MPam(to the power of)0.5) was achieved by the incorporation of 60% w/w inorganic silica particles. The application of hybrid concepts by utilizing synergistic toughening mechanisms (HBP and silica), revealed only moderate benefits within the investigated highly crosslinked materials. As the examined epoxy/anhydride formulations are generally considered for high temperature applications, it was essential to determine their long-term thermooxidative ageing performance. The long-term thermo-oxidative ageing behaviour has been investigated by means of thermo-gravimetric analysis (TGA), dynamic mechanical analysis (DMA) and vibrational infrared spectroscopy (FT-IR) methods with special emphasis on fundamental understanding of the ageing mechanism. Effects of the thermal ageing on the characteristic viscoelastic and flexural behaviour, weight-loss and oxidation susceptibility of the examined epoxy networks were assessed and discussed, thus providing an understanding of the principal material endurance properties. The thermo-mechanical behaviour and the related structural changes with thermal ageing were examined by Cole-Cole plots in combination with a molecular theory previously developed by Perez. It was demonstrated that this new methodology provides a connection between conversion, glass transition temperature, and mechanical relaxation data and allows a fundamental molecular interpretation with respect to physical and chemical ageing phenomena. A variety of thermo-gravimetric experiments were carried out in order to determine and model the specific weight-loss profile as a function of anhydride nature and ageing temperature. The influence of different inorganic fillers on the thermooxidative response was systematically studied. Different models were applied to extract meaningful kinetic parameters in order to describe the thermo-oxidative degradation and to facilitate an extrapolation of weight-loss data outside the experimental time- and temperature-scale. FT-IR micro ATR-spectroscopy was used to identify, localize and quantify the complex oxidation behaviour. A thermo-oxidative degradation mechanism, that involved predominantly radical oxidation processes and C-N as well as C-O chain scissions, was proposed to account for the experimental observations. Specific oxidation-front profiles were constructed to describe the heterogeneous oxidation processes. Finally, the comprehensive material characterization of these novel co-anhydridecured amino-glycidyl resins in terms of curing mechanism and kinetic, deformation and fracture behaviour, and thermo-oxidative ageing performance, allows the assessment of the potential of these materials for demanding applications in electrical and electronic industries.

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Firms frequently use brand extension strategies to enter new product categories. Another type of entry strategy is co-branding by effectively exploiting the equity of both constituent brands. Co-branding may effectively drive consumer preferences if consumers believe the combination of two brands offers a better solution than either one separately. However, there is also the risk that consumers may get confused with the combination, or have perceptions of strengths regarding one of the brands diluted, leading to the failure of this strategy. While much has been written on brand-category extension, despite its prevalence, the use of co-brands to enter a new category has attracted relatively little attention. In this study, the author models the effects on consumer perceptions and preferences of combining two brand names for a new product. The proposed model provides a mechanism to represent how consumers’ prior attribute beliefs about constituent brands, the extendibility of the brands into the extension category, the compatibility between the constituent brands, and the uncertainty associated with them can jointly determine their preferences for the co-branded product. The contribution that this model enables is a means to study co-branding and new category entry simultaneously, by assessing the drivers of consumer preference for a co-brand in a new product category. An empirical study is designed to test the model, using real brands and hypothetical extensions and co-brands. Theoretical contributions and managerial implications of this study are discussed.

Master of Engineering (Research) / In many multi-objective missions there are situations when actions based on maximum information gain may not be the `best' given the overall mission objectives. In addition to properties such as entropy, information also has value, which is situationally dependent. This thesis examines the concept of information value in a multi-objective mission from an information theory perspective. A derivation of information value is presented that considers both the context of information, via a fused world belief state, and a system mission. The derived information value is used as part of the objective function for control of autonomous platforms within a framework developed for human robot cooperative control. A simulated security operation in a structured environment is implemented to test both the framework, and information value based control. The simulation involves a system of heterogeneous, sensor equipped Unmanned Aerial Vehicles (UAVs), tasked with gathering information regarding ground vehicles. The UAVs support an e ort to protect a number of important buildings in the area of operation. Thus, the purpose of the information is to aid the security operation by ensuring that security forces can deploy e ciently to counter any threat. A number of di erent local controllers using information based control are implemented and compared to a task based control scheme. The relative performance of each is examined with respect to a number of performance metrics with conclusions drawn regarding the performance and exibility of information value based control.

The aim of this research was to examine the teacher’s facilitative role to engage students in Values Education (Curriculum Council, 1998) based on a cooperative and collaborative learning pedagogy. The study was conducted in a primary school classroom with thirty-one year 4/5 students aged 9-10 years of age. During the research process the core shared values underpinning the Western Australian Curriculum Framework (Curriculum Council, 1998) provided the foundation to negotiate agreements for behaviour based on The Tribes process (Gibbs, 2001), which included mutual respect, in order to foster a safe, supportive and democratic classroom culture. The Tribes process was used to operationalise the teaching of values, social skills, cooperation and collaboration. Hart’s (1992) collaborative framework informed the organisation of the classroom to create the conditions that supported collaboration amongst peers and the teacher. An action research approach was used to reflect on the classroom context and provide a focus for a range of qualitative research methods. Multiple data sources such as teacher observations, interviews, student and teacher reflection logs and sociograms were used to triangulate findings from parents, students and teachers. A sociocultural perspective (Vygotsky, 1978) provided the conceptual framework for this study as the underlying assumption is that students learn from each other, mediated by the teacher or more capable peers. The focus on the action within the social context during the development of interpersonal relationships is a key feature of peer mediated learning, which complemented the processes chosen by the teacher researcher to elucidate how a safe, supportive and democratic classroom was created. Class meetings, group work and reflective practices were used to scaffold students’ understandings of interpersonal relationships to promote a culture that was consistent with Australia’s democratic traditions. Reflective practices in the classroom provided opportunities for new perspectives to be developed, as new knowledge and experiences were integrated with existing personal practical knowledge. The major findings reflected the foci of student and teacher conversations about students’ interpersonal skills and their ability to get along with each other. In the first phase of the study establishing positive ‘relationships’ based on trust, through teambuilding activities provided the impetus for the next phase of the study about ‘leadership’. This phase continued for most of the study, and provided authentic opportunities for students to develop leadership skills, which permeated the last phase of the study about ‘friendships’. Students established mutually beneficial relationships that broadened their views about discriminatory behaviours, friendship and leadership. The major conclusions drawn from the study is that teachers play a significant role in mediating positive relationships amongst peers. Further, it was evident that the explicit teaching of core shared values (Curriculum Council, 1998) provided the foundations of productive and active citizenship during the process of creating the conditions for a safe, supportive and democratic classroom.