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1	A Mixed Methods Study of Class Size and Group Configuration in Online Graduate Course Discussions Qiu, Mingzhu 01 September 2010 (has links) Class size has long been recognized as a factor affecting achievement in face-to-face contexts. However, few studies have examined the effects of class size in online courses, or the effects of dividing an online class into smaller discussion groups. The current study examined the relationship between class size and the use of grouping strategies on note reading, note writing, and collaborative discussions in online graduate-level courses. This mixed-methods study analyzed tracking logs from 25 graduate-level online courses using Web Knowledge Forum (25 instructors and 341 students) and interviews from 10 instructors and 12 graduate students with diverse backgrounds. The quantitative and qualitative data analyses were designed to complement each other. Findings suggested 13 to 15 as an optimal class size and four to five as an ideal subgroup size. Not surprisingly, the results revealed that, as class size increased, the total notes that participants read increased significantly. However, as class size increased, the percentage of course notes that students read decreased significantly (i.e., students were reading a smaller proportion of the course notes). In larger classes, participants were more likely to experience information overload and students were more selective in the notes that they read. A significant positive correlation was found between class size and total notes written. Students’ note size and grade-level score were negatively correlated with class size. The data also suggest that the overload effects of large classes can be minimized by dividing students into small groups for discussion purposes. Interviewees felt that the use of small groups in large classes benefited their collaborative discussions. The preceding results underscore the importance of using small discussion groups when class sizes are large. The research concludes with a list of pedagogical recommendations and suggests new software features that may help enhance learning in online courses. class size group configuration mixed methods study graduate course discussions 0710
2	A Mixed Methods Study of Class Size and Group Configuration in Online Graduate Course Discussions Qiu, Mingzhu 01 September 2010 (has links) Class size has long been recognized as a factor affecting achievement in face-to-face contexts. However, few studies have examined the effects of class size in online courses, or the effects of dividing an online class into smaller discussion groups. The current study examined the relationship between class size and the use of grouping strategies on note reading, note writing, and collaborative discussions in online graduate-level courses. This mixed-methods study analyzed tracking logs from 25 graduate-level online courses using Web Knowledge Forum (25 instructors and 341 students) and interviews from 10 instructors and 12 graduate students with diverse backgrounds. The quantitative and qualitative data analyses were designed to complement each other. Findings suggested 13 to 15 as an optimal class size and four to five as an ideal subgroup size. Not surprisingly, the results revealed that, as class size increased, the total notes that participants read increased significantly. However, as class size increased, the percentage of course notes that students read decreased significantly (i.e., students were reading a smaller proportion of the course notes). In larger classes, participants were more likely to experience information overload and students were more selective in the notes that they read. A significant positive correlation was found between class size and total notes written. Students’ note size and grade-level score were negatively correlated with class size. The data also suggest that the overload effects of large classes can be minimized by dividing students into small groups for discussion purposes. Interviewees felt that the use of small groups in large classes benefited their collaborative discussions. The preceding results underscore the importance of using small discussion groups when class sizes are large. The research concludes with a list of pedagogical recommendations and suggests new software features that may help enhance learning in online courses. class size group configuration mixed methods study graduate course discussions 0710
3	Response of concrete pavements under moving vehicular loads and environmental effects Darestani, Mostafa Yousefi January 2007 (has links) The need for modern transportation systems together with the high demand for sustainable pavements under applied loads have led to a great deal of research on concrete pavements worldwide. Development of finite element techniques enabled researchers to analyse the concrete pavement under a combination of axle group loadings and environmental effects. Consequently, mechanistic approaches for designing of concrete pavements were developed based on results of finite element analyses. However, unpredictable failure modes of concrete pavements associated with expensive maintenance and rehabilitation costs have led to the use of empiricalmechanistic approach in concrete pavement design. Despite progressive knowledge of concrete pavement behaviour under applied loads, concrete pavements still suffer from deterioration due to crack initiation and propagation, indicating the need for further research. Cracks can be related to fatigue of the concrete and/or erosion of materials in sub-layers. Although longitudinal, midedge and corner cracks are the most common damage modes in concrete pavements, Austroads method for concrete pavement design was developed based on traditional mid-edge bottom-up transverse cracking introduced by Packard and Tayabji (1985). Research presented in this thesis aims to address the most common fatigue related distresses in concrete pavements. It uses comprehensive finite element models and analyses to determine the structural behaviour of concrete pavements under vehicular loads and environmental effects. Results of this research are supported by laboratory tests and an experimental field test. Results of this research indicate that the induced tensile stresses within the concrete pavement are significantly affected by vehicle speed, differential temperature gradient and loss of moisture content. Subsequently, the interaction between the above mentioned factors and concrete damage modes are discussed. Typical dynamic amplifications of different axle groups are presented. A new fatigue test setup is also developed to take into consideration effects of pavement curvature on fatigue life of the concrete. Ultimately, results of the research presented in this thesis are employed to develop a new guide for designing concrete pavements with zero maintenance of fatigue damage. dynamic analysis dynamic amplification finite element analysis finite element model static analysis axle group loads critical axle group configuration critical position of axle groups tyre pavement interaction stress distribution fatigue failure concrete pavement distresses corner cracking longitudinal cracking transverse cracking top-down cracking bottom-up cracking boundary conditions debonding layer temperature effects loss of moisture contents shrinkage effects curling induced stress warping stress pavement curvature field test laboratory text experimental study truck load JPCP JRCP CRCP SAST SADT TAST TADT TRDT QADT

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