In this study, the author investigated factors that influence the direct measurement of cognitive load using the dual-task method. The dual-task method is an unambiguous and objective technique to measure cognitive load. The primary task was to master content in a lesson about the Autonomic Nervous System. The secondary task was to respond to a symbol that changed colour by pressing the Enter key. The time between the symbol changing colour and the response of the student was measured. Two versions of the multimedia program tested the influence of the presentation format and instructional strategy on cognitive load. Each version of the program was further subdivided into four lessons, which were used to test the influence of the position of the secondary task on the cognitive load. All the data was collected electronically. The statistical analysis revealed that the position of the secondary task does not influence cognitive load (F (1, 2661) = 3.25, p = 0.071). The presentation format and instructional strategy used in this study however did result in a significant difference between the cognitive load of the two versions. The mean cognitive load of the version using animation was 6.408 and that of the version using predominantly static images and text was 5.684. This difference was found to be highly significant (F (1, 2661) = 52.39, p <.0001). It was concluded that using animation to present content required more mental effort by participants than using images and text to present the same content. / Dissertation (MEd (Computer-Integrated Education))--University of Pretoria, 2007. / Curriculum Studies / unrestricted

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Synergism is an art presentation designed to use multimedia concepts to heighten audience involvement in the work. Although primarily sound oriented, its skeletal structure is literary. The music expands upon the text to communicate the inexplicable or irrational element of its meaning to those faculties which determine emotional response. This process is aided by a modicum of environmental control achieved through stage lighting effects.

This dissertation devotes itself to algorithmic approaches to the problem of scalable multicast with network coding. Several original contributions can be concluded as follows. We have proved that the scalable multicast problem is NP-hard, even with the ability to perform network coding at the network nodes. Several approximations are derived based on different heuristics, and systematic approaches have been devised to solve those problems. We showed that those traditional routing methods reduce to a special case in the new network coding context. Two important frameworks usually found in traditional scalable multicast solutions, i.e. layered multicast and rainbow multicast, are studied and extended to the network coding scenario. Solutions based on these two frameworks are also presented and compared. Suprisingly, these two distinctive approaches in the traditional sense become connected and share a similar essence of data mixing in the light of network coding. Cases are presented where these two approaches become equivalent and achieve the same Performance. We have made significant advances in constructing good solutions to the scalable multicast problem by solving various optimization problems formulated in our approaches. In the layered multicast framework, we started with a straight-forward extension of the traditional layered multicast to the network coding context. The proposed method features an intra-layer network coding technique which is applied on different optimized multicast graphs. Later on, we further improved this method by introducing the inter-layer network coding concept. By allowing network coding among data from different data layers, more leverage is gained when optimizing the network flow, thus higher performance is achieved. In the rainbow multicast framework, we choose uneven erasure protection (UEP) technique as the practical way of constructing balanced MDC, and optimize this MDC design using the max-flow information of receivers. After the MDC design is finalized, a single linear network broadcast code is employed to deliver MDC encoded data to receivers while satisfying the individual max-flow of all the receivers. Although this rainbow multicast based solution may sacrifice the performance in some cases, it greatly simplifies the rate allocation problem raised in the layered multicast framework. The use of one single network code also makes the network codes construction process a lot clearer. Extensive amount of simulation is performed and the results show that network coding based scalable multicast solutions can significantly outperform those traditional routing based solutions. In addition to the imaginary linear objective function used in the simulation, the practical convex objective function and real video data are also used to verify the effectiveness of the proposed solutions. The role of different parameters in the proposed approaches are analyzed, which gives us more guidelines on how to fine-tune the system. / Thesis / Doctor of Philosophy (PhD)

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The availability of computer systems has resulted in an increased use of computers for teaching and learning in education. Computers and peripheral hardware enable educators to incorporate video, sound, and animation into instruction. Authoring software provides another level for computer use by allowing educators to develop and use multimedia instruction and programs designed for specific learning outcomes. New technologies, such as the micro computer as an instructional tool, are providing teachers and learners the opportunity to explore alternative ways to learn (Hansen, 1995). If these new technologies are to become an effective component of the teaching-learning environment, educators and media developers must have access to research-based information that will guide them in selecting and developing appropriate media and instructional applications. Since most learning begins as a cognitive process (Schwaller, 1995), research dealing with instructional methods tends to focus on the cognitive domain, which would more likely yield results that would pertain to a large number of disciplines, educators, and media developers. Unfortunately programs such as technology education, which include experiential activities as an integral part of the learning process (Korwin & Jones, 1990), should not rely on cognitive performance alone as the sole indicator of successful completion of the learning objectives. In the Technology Education classroom, hands-on experiential activities add value to the instruction and require various degrees of psychomotor performance. While psychomotor learning should not be considered the sole purpose of technology education, it is a most viable and significant aspect of learning and performance in technology education. Effectively presenting psychomotor content to the learner could increase performance of instructional objectives, thus providing an enriched learning environment. This study was designed to investigate the effect of visual-only, verbal-only, and visual/verbal instructional methods utilizing Computer- Based Instruction (CBI) as the vehicle, on the performance of psychomotor skills and knowledge. An investigation of the relationship between presentation mode, gender, and psychomotor performance based on direct product evaluation was conducted. Analysis results suggest that during instruction, the level of performance of a psychomotor task increases with the use of visual/verbal CBI. In addition, gender did not significantly influence the level of performance regardless of the presentation mode. Secondary analysis of the data suggest that visual/verbal CBI has no significant influence on the level of performance after a time interval of approximately 11 days. Posttreatment survey results indicate participants had a higher level of satisfaction with the visual/verbal CBI. / Ph. D.

This thesis provides a novel architecture for the creation and management of virtual multimedia adaptation services offered by a multimedia-enabled cloud. The aim of the proposed scheme is to provide an optimal yet a transparent user access to adapted media contents while isolating them from the heterogeneity of the utilized devices, diversity of media formats, as well as the details of the adaptation services and performance variations of the underlying network. This goal is achieved through the development of service virtualization models that provide various levels of abstraction of the actual physical services and their performance parameters. Such virtual models offer adaptation functions by comprising adaptation services with accordance to their parameters. Additionally, parameters describing the functional specifics of the adaptation functions, as well as multimedia content features, are organized into a hierarchical structure that facilitates extraction of the virtual models capable of satisfying the conditions expressed by the user requests. At the same time the paramter/feature organization structure itself is flexible enough to allow users to specify media delivery requests at various levels of request details (e.g., summarize video vs. drop specific frames). As a result, in response to a user request for a multimedia content, an optimal virtual service adaptation path is calculated, describing the needed media adaptation operations as well as the appropriate mapping to the physical resources capable of executing such functions. The selection of the adaptation path is done with the use of a novel performance-history based selection mechanism that takes into account the performance variations and relations of the services in a dynamically changing environment of multimedia clouds. A number of experiments are conducted to demonstrate the potential of the proposed work in terms of the enhanced processing time and service quality.

This thesis presents novel techniques to index multiple media streams in a digi- tally captured presentation. These media streams are related by the common content in a presentation. We use relevance curves to represent these relationships. These relevance curves are generated by using a mix of text processing techniques and distance measures for sparse vocabularies. These techniques are used to automatically detect slide boundaries in a presentation. Accuracy of detecting these boundaries is evaluated as a function of word error rates.