Une étude des faunes de conodontes du Dévonien supérieur (Frasnien) a été réalisée sur deux coupes algériennes de la plate-forme occidentale du Sahara, Marhouma sud (bassin de l'Ougarta) et Ben Zireg (bassin de Béchar). Dans la coupe de Marhouma le Frasnien apparaît complet, tandis qu'une lacune du Frasnien inférieur est enregistrée à Ben Zireg. La limite entre les étages Frasnien et Famennien a été précisément localisée.Les corrélations entre ces coupes montrent une forte condensation des dépôts au Frasnien moyen à Ben Zireg, alors qu'au même moment d'épaisses séries argilo-carbonatées s'accumulent dans l'Ougarta. Au cours du Frasnien supérieur un changement de la structuration des bassins est constaté avec l'homogénéisation du taux d'accumulation dans les deux secteurs.Afin de reconstituer les environnements de dépôt du Frasnien, nous avons mené une étude multidisciplinaire basée sur la sédimentologie des faciès, la susceptibilité magnétique, les biofaciès à conodontes et les morphogroupes de foraminifères agglutinés. La combinaison de ces outils révèle qu'au cours du Frasnien, la plate-forme saharienne algérienne était assimilable à un domaine de rampe externe, carbonatée, de faible pente, avec des zones proximales dominées essentiellement par des communautés pélagiques, passant à des zones distales dominées par des faciès boueux et nodulaires à rares faunes. L'essentiel des dépôts était situé sous/ ou en limite de/ l'action des vagues de tempêtes.La coupe de Marhouma représente une coupe de référence pour l'étude des dépôts anoxiques du Frasnien. Certains de ces niveaux ont pu être rapportés à des événements anoxiques globaux tels que le Middlesex et le Rhinestreet, datés du Frasnien moyen, et le Kellwasser supérieur dans le Frasnien supérieur. Pour la coupe de Ben Zireg, seul le facies relatif aux Kellwasser inférieur et supérieur a été identifié.L'évolution temporelle de ces différents paramètres a permis également de proposer une courbe de variations du niveau marin pour la partie nord du Gondwana. À long terme, le Frasnien est caractérisé par une tendance transgressive entrecoupée de tendances régressives mineures. La fin du Frasnien est marquée une régression majeure lors de l'événement Kellwasser, avant la transgression du Famennien inférieur. / A study of the conodont faunas from the Upper Devonian (Frasnian) has been realised in two sections located on the Algerian Sahara platform: south Mahrouma (Ougarta basin) and Ben Zireg (Bechar Basin). At Mahrouma, the Frasnian seems to be complete, but the lower Frasnian is absent in Ben Zireg. The boundary between the Frasnian and the Famennian has been precisely located.The correlations between the two sections show a strong condensation of deposits during the middle Frasnian in Ben Zireg, whereas thick series of argilites and carbonates accumulated in the Ougarta basin. During the Upper Frasnian a change in dynamic basin structure is observed when accumulation rates become homogeneous in the two areas.In order to reconstitute Frasnian depositional environments, a multidisciplinary study based on sedimentology of the facies, magnetic susceptibility, conodont biofacies and morphogroup analysis of agglutinated foraminifera has been undertaken. The combination of these tools indicates that during the Frasnian, the algerian platform took part of a slightly inclined outer carbonated ramp domain. The proximal areas were essentially dominated by pelagic communities, the distal areas being dominated by muddy and nodular facies with rare faunas. The major part of the deposits was located under or at the limit of tempest wave action.The Mahrouma section represents a reference for investigations on Frasnian anoxic deposits. Some of its levels could have been related to global anoxic events such as the Middlesex and the Rhinestreet that are dated Middle Frasnian, as well as the Upper Kellwasser at the top of the Frasnian. In the Ben Zireg section, only the facies related to both the Lower and Upper Kellwasser events were identified.The temporal evolution of these different proxies allows in addition to propose a sea-level curve for the northern part of Gondwana. In the long term, the Frasnian is characterized by a transgressive trend interrupted by intermittent minor regressive trends. The end of the Frasnian is marked by a major regression during the Upper Kellwasser event, just before the Lower Famennian transgression.

This study sought to determine if an online course designed and delivered in Second Life can meet the needs of higher education students with dyslexia. the course design incorporated strategies from Gagne’ and Briggs’ principles of instruction, Gagnon and Collay’s constructivist learning design, Powell’s key learning needs of dyslexics, and elements of universal design. Specific design elements are discussed including screen captures from the design. the study employed a mixed methods approach incorporating an online survey, recorded observation session, and two follow up interviews. the observation session and interviews were only completed by the sample population of eight participants, which included three participants with dyslexia and five participants without dyslexia. the sample population was selected using purposeful sampling techniques to ensure the widest representation of the population with a small sample. Extensive excerpts of the sample participants’ interview responses are presented and discussed, including participants’ suggestions for improving the course design. Key findings from all three data sources are discussed. Finally, implications for instructional design and special education and suggestions for further research are presented.

>Magister Scientiae - MSc / Three-dimensional (3D) graphic representations of geographic environments have become commonplace in a range of elds. These representations are often an attempt to represent both geographic forms, as well as the relationships that exist between them. In contrast to other elds, the use of 3D geological models in the visualisation of the subsurface environment is relatively new. Additionally, these 3D geological models are traditionally created through the painstaking process of manual development methods. As such, the models developed are unable to fully utilise the wealth of geological data that is collected during subsurface exploration. Therefore, the objective of this research was to create a 3D geological prototype that allowed for the visualisation of underground resource reservoirs in a faster, easier and more aesthetically appealing manner. To achieve the objectives of this research, the problem was tackled holistically by considering both the theoretical and practical components of the research. Some theoretical components that were considered are: well log wireline log data composition, the information that can be extracted from each well log component, geological data interpolation as well as geological visualisation. Utilisation of the theoretical component of this research facilitated the development of a programme that modelled and visualised sub-surface environments. The programme applied the information from numerous well log datasets and interpolated the various geological layers that could be found within a region.

We investigate the problem of establishing trust in service-oriented environments. We focus on providing a reputation framework that would enable trust-based interactions with and amongst Web services. We define methods for the creation of reputation information, its collection, and assessment that are robust in the face of a variety of attacks. Our framework (denoted RATEWeb) supports a cooperative model in which Web services share their experiences of the service providers with their peers through feedback ratings. The different ratings are aggregated to derive a service provider's reputation. This in turn is used to evaluate trust. For situations where rater feedbacks are scarce, we use statistical forecasting (particularly, a Hidden Markov Model) to ascertain trust. The approaches and techniques developed under the RATEWeb framework facilitate the optimal selection and/or composition of Web services based on service reputations. We conduct an extensive performance study (analytical and experimental) to assess the fairness and accuracy of the proposed techniques. / Ph. D.

Augmented reality, the superimposing of graphics or text onto an actual visual scene, is intended to enhance a user's understanding of the real world. This research examines the perceptual, cognitive, and human factors implications of combining integrally designed computer-generated imagery with real world scenes. Three experiments were conducted to test the theoretical and practical consequences of integral perception in augmented reality. The first experiment was a psychophysical study that had participants subjectively assess the integrality of 32 scenes comprising four different augmented reality object environments (computer, brain, text, and liquid dynamic model), projected at two transparency levels (opaque, and semi-transparent), and presented with four different graphic textures (color, grayscale, white, and wireframe). The second experiment expanded the psychophysical integrality assessment of augmented scenes to 32 different images composed of four new environments (housing development, computer lab, planetary photo, and trees in countryside), with multiple computer-generated graphics (two, four, six, and eight), at two levels of integrality as defined by experiment one (high, low). The third experiment was an applied study that had two phases: 1) learning tasks using three augmented environments; and, 2) assembly tasks using eight augmented video instructions. The computer-generated graphics for each phase of experiment three were presented at two levels of integrality (high, low) as defined by experiment one. The primary results of the three experiments show that augmented reality scenes with computer-generated imagery presented transparently and in color were perceived most integrally; increasing the number of graphics from two to eight decreased integral perception; and, high integral graphics aided performance in learning and real assembly tasks. From the statistical results and experimenter observation of the three experiments, guidelines for designing integrally perceived graphics in augmented environments were compiled based on principles of human factors, perception, and graphic design. The key themes of the design guidelines were: 1) maintaining true shape information in the computer-generated graphics 2) using highly realistic graphics for naturalistic augmented settings; 3) considering the hardware limitations of the augmented system, particularly the display; and, 4) designing appropriately for the task (simple, complex, hands-on, cognitive, dynamic, static, etc.). / Ph. D.

Massively multiplayer online environments continue to grow in popularity, with cur- rent technical designs based upon a well-proven client-server model. This approach has some inherent limitations, high costs to provision server resources for peak demands and restriction of the maximum number of concurrent participants within a virtual environ- ment. Incorporating peer-to-peer (P2P) techniques provides developers the opportunity to significantly reduce costs, while also breaking through the barrier of the number of concur- rent participants within a single virtual environment. This dissertation presents a hybrid P2P design incorporating a managed server along with a Voronoi-based P2P overlay for the development of massive virtual environments. In this design, the managed server en- sures a secure computing environment and long-term persistent storage, with the virtual environment simulation distributed among the peers, ensuring computational scalability.

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The growth of the World Wide Web has prompted many businesses to develop electronic commerce (e-commerce) as a domain where consumers can conveniently purchase their products (Chittaro& Ranon, 2002). Marketing and Human - Computer Interaction (HCI) research has focused on the ways interactivity can improve purchasing experience. One particular technique is through the use of computer models of products known as visual object representations (Ozok& Komlodi, 2009). Research on visual product representations is focused on models of objects typically purchased in a store, such as clothing and electronics, which can usually be manipulated and rotated as desired (Ozok& Komlodi, 2009). There seems to be a gap in the literature regarding computer models for which consumers actually do not have an established mental models. Computerized walk-through models allow users to virtually navigate a space as well as to view a model of a living space from different orientations. An experiment was conducted on 100 participants to investigate computerized walk-through models and the role the type of model and workload plays in the amount of knowledge gained about the layout and consumer preference. Participants navigated a computerized walk-through model or a two dimensional picture set of a hotel room (low complexity) or apartment (high complexity) .Then they completed a series of surveys. Results indicate that two-dimensional models were best for learning the layout of a high complexity model and that three-dimensional models were better for learning the layout of a low complexity model. Results have implications for virtual model use in education and the military.

One of the oft cited reasons for virtual environments is that they provide experiences with places one would never be able to visit and to perform tasks that would otherwise be dangerous, or inaccessible. The ability to become transported to another environment, such that you think you are "there," is known as presence. Existing presence literature focuses largely on the sensory aspects of virtual environment experiences. However, there is more to experience than what is sensed. This dissertation investigates the theoretical components of holistic experiences in virtual environments. In order to explore the relationship between experiential design and presence, a new evaluation tool was needed. This ultimately led to the development of the Virtual Experience Test. To validate the Virtual Experience Test, an experiment was designed that utilized subjective evaluations regarding game-play in the commercial game Mirror's Edge. Measures of experiential design, flow, and presence were taken and the relationships between the measures analyzed. The results of this research showed that environments utilizing holistic designs result in significantly higher presence. Furthermore, this study produced a validated measure of holistic experience that designers could use to evaluate their virtual environments.

The current Accreditation Council for Occupational Therapy Education (ACOTE) Standards include a provision for the use of experiential learning methods as level I fieldwork experiences by entry-level occupational therapy (OT) education programs (ACOTE, 2018). Included in these experiences are two specific types of simulation: simulated environments and standardized patients. Earlier versions of the ACOTE Standards did not allow for the use of simulation as level I fieldwork experiences. This provision may help mitigate a shortage of level I and level II fieldwork placements and allow academic programs to provide consistent quality level I fieldwork across students (American Occupational Therapy Association [AOTA], 2017). This use of simulation as a fieldwork training method is an emerging area of OT education that has limited research on its use and best practice. This doctoral project sought to contribute to the existing knowledge by conducting a research study which investigated the use of both simulated environments and standardized patients by academic programs, as well as identifying the primary supports and barriers to its implementation. The project included the creation, distribution, and analysis of a national survey of entry-level OT programs. The survey found that the main barrier and support to implementation of simulation was funding and that private institutions are more likely to utilize standardized patients than public institutions. The results of this study will help inform future ACOTE Standards, provide both the American Occupational Therapy Association and ACOTE with additional information to help determine how to best provide resources for academic programs that facilitate successful implementation of the simulation methods, and help identify programs that can participate in the dissemination of best practice in the use of simulation as fieldwork experiences. The author recommends that ACOTE should also consider mandating the use of simulation, along with other experiential learning activities, as partial fulfillment of level I fieldwork requirements, to allow for better access to funding, decrease the fieldwork burden on traditional fieldwork sites, and allow for more consistent level I fieldwork experiences.