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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

3D seismic surface multiple attenuation : algorithms and analysis /

Alaslani, Abdulaziz Saleh, January 2001 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references (leaves 192-200). Available also in an electronic version from UMI Company.
52

Priming the Pump: Reflection as a Catalyst for Transfer

Griffith, Tiffany Erin 01 May 2017 (has links)
One of the main expectations the university community has for First Year Composition (FYC) is that it will help students to become better writers and prepare them for the work they will do in subsequent courses, including writing in their own disciplines. In order for this to happen, students have to be able to transfer their knowledge. Because transfer does not happen automatically, it must be fostered in a way that encourages students to recognize and articulate what they have learned and are learning. Articulation of learning and of awareness of writing development moves students toward transfer, and reflection provides the means for students to address their learning. For students to learn how to transfer, we must teach for transfer, doing so in a way that promotes both transfer and their awareness of its possibility. Context-sensitive discourse analysis provides a glimpse at students’ perceptions of their writing development (a necessary component for transfer) as well as potential transfer and cues to trigger it. This research conducted at a small, private university in the Midwest collected reflective essays from first-year students; I coded the essays according to comments addressing what students’ papers show about them as students and writers, what revisions and changes they would want readers to notice, what they learned over the semester, what they said about their growth and its ongoing nature, etc. The students’ comments provide a glimpse at their awareness of the ongoing nature of their development and the places where the awareness of transfer emerges, which, by extension, can show us where we can intervene and work with students to promote transfer.
53

The nature of mathematics teachers’ reflective practice

Posthuma, Anna Barbara 25 April 2012 (has links)
Thoughts about reflection and reflective practice have evolved over many decades, through carefully constructed theory and research applications, mainly based on the work of Dewey (1933) and Schön (1983). Evidence also exists in the literature that the ability to reflect on practice is considered a necessity for effective instruction (Sowder, 2007). By reflecting critically teachers become more positive in the search for a new understanding of their teaching practice and design more ways to deal with the challenges that confront them daily. When teachers act reflectively, they consider carefully the problems in their own teaching and think about how those problems are related to their educational or social context. They are aware of the consequences of their teaching and how their own assumptions or beliefs can influence their teaching. This main purpose of my research study was to explore the nature of mathematics teachers’ reflective practice in the context of lesson study. To achieve this aim, an in-depth exploration of five mathematics teachers’ reflection before, during and after teaching a lesson was conducted. The possible relationship between these teachers’ reflection and their classroom practice was also examined. The research also aimed to explore whether and how mathematics teachers’ reflections differ from the conceptualisations of reflection in classroom practice as found in the literature. Contextual factors that might influence the nature of mathematics teachers’ reflective practice were also investigated. My findings indicate that the mathematics teachers in my sample have a limited understanding of the concept of reflection. Furthermore, based on lesson plan analysis, there was no evidence that these teachers reflect-for-action. However, they all reflected on-action verbally and in writing, and three of the five teachers reflected-in-action while teaching. They all reflected on Level R1 (recall level of reflection) and Level R2 (rationalisation level of reflection) and three teachers reflected critically on their learners’ understanding of mathematics and their own teaching of concepts towards the end of the research project (Lee, 2005). Language and the lesson study group experience emerged as contextual factors that seemed to influence the teachers’ reflection. Although the research study’s results cannot be generalised due to the small sample, I believe that through engaging in the lesson study experience the five teachers of this study improved their reflective practice, reporting an increase in self-knowledge and finding new ways of teaching mathematics to learners. / Thesis (PhD)--University of Pretoria, 2011. / Science, Mathematics and Technology Education / unrestricted
54

Analysis and modeling of high-resolution multicomponent seismic reflection data /

Guy, Erich D. January 2002 (has links)
No description available.
55

Using a Reflective Process to Implement Electronic Portfolios

Falls, Jane Ann 10 December 2001 (has links)
This case study documents the stages, procedures, and interactions between a researcher and a public school teacher during the implementation of electronic portfolios. The primary topics highlighted are: general information regarding portfolios; reflection; and issues that arose during the study. The classroom teacher in this particular study worked in Southwest Virginia at a modern vocational facility, and she had expressed a desire to master the various technologies necessary to implement electronic portfolios. The researcher was competent in these technologies; her objective was to ascertain the methods and materials, and other processes in which electronic portfolios could be implemented in a public school setting. The collaboration between the researcher and the teacher provided for an arrangement wherein the teacher often learned the technologies simultaneously, along with her students. The researcher's ongoing assistance also offered the teacher time to concentrate on the various management aspects of the project.Reflection was developed as a critical component of the process. It was instrumental for the students, the teacher, and the researcher. Students were required to write "reflections" about the artifacts they had chosen for their electronic portfolios. The researcher and the teacher would meet regularly to reflect on the project's status; methods and materials; management issues; and even to reflect on reflection itself, and the methods to take the students deeper as it pertained to their reflections on any given artifact.Three aspects of the process revealed themselves to be major components that would be inescapable considerations for any classroom teacher who wished to implement electronic portfolios: the technology; the reflective writing process; and management issues. The management issues generally pertained to time issues. This study was successful because it proved to identify the essential components of an electronic portfolio project. And, lastly the collaboration between the teacher and the researcher proved to be successful because the two major objectives of the study were achieved: the teacher mastered the technology (and the process) necessary to implement electronic portfolios; and the researcher identified, correlated, and recorded this discovery so that it might be replicated. / Ph. D.
56

An Example of Utilizing Students' Reflections in e-Portfolios for Program Evaluation: A Qualitative Content Analysis

Wu, Yanzhu 05 May 2014 (has links)
As the growth of online programs in higher education accelerated across the nation, concerns have been addressed regarding the quality of online programs. The evaluation of programs for quality assurance has become an important component of successful online programs (Kindgren, Nilsson, and Wiklund, 2012, Martinez, Liu, Watson, and Bichelmeyer, 2006). Deggs and Weaver (2009) stated that student perception is "essential to improving the quality of instruction in higher education" (p. 41). In the online program evaluation literature, majority of evaluation studies commonly collected students' perceptions of their learning outcomes and their learning experiences through survey questionnaires. Few studies had been conducted on using students' reflections in e-portfolios for program evaluation in higher education. The purpose of this study was to explore how students' reflections in their e-portfolio can be used as a mechanism for program evaluation. This study employed a qualitative content analysis method. Seventy students' reflections in their e-portfolios of an online master's program were collected. Three types of reflections in e-portfolios have been reviewed and analyzed: (1) students' reflections on their previous approaches to the five tasks of instructional design including design, development, utilization, management, and evaluation; (2) the students' reflections on their current approaches to these five instructional design tasks; and (3) the perceptions on their learning experiences in this online master's program. Two overarching themes emerged from the students' reflections including students' perceptions on their learning outcomes and their learning experiences in the program. The results of the study indicated that students' reflections in their e-portfolios provide another dimension of qualitative information for program evaluation with respect to students' perceptions, and this qualitative data can be used in conjunction with other methods of data collection to conduct a comprehensive evaluation of online programs. / Ph. D.
57

Shock wave propagation into a valley

Whitehouse, Joanne 30 October 2006 (has links)
Student Number: 0008522F Master of Science Faculty of Engineering & The Built Environment School of Mechanical, Industrial & Aeronautical Engineering / An aircraft travelling at supersonic speeds close to the ground generates a bow wave, which is reflected off the ground surface. When the aircraft enters a valley, the three-dimensional bow wave is reflected off the valley walls, such that it could focus behind the aircraft. Complex threedimensional wave surfaces will result. The real situation of an aircraft entering a valley can be modelled and tested experimentally in a shock tube. To simulate the process a planar shock wave, generated in a shock tube, is moved over several notched wedge configurations. Schlieren photographs were produced to identify the resulting complex three-dimensional wave structures and then verified by three-dimensional CFD. The valley geometries investigated are rectangular, triangular, parabolic and conical. Three hill geometries were also investigated. The three-dimensional reflected surfaces from the rectangular valleys were found to vary only slightly as the valley floor inclination is increased. As the incident wave interacts with both the wedge and valley floor surfaces two prominent reflections occur. A primary reflected wave surface is generated from regular reflection off the wedge. This surface flows over into the valley contacting the incident wave at a second contact point. A secondary reflected wave is found underneath the primary reflected wave, generated due to Mach reflection occurring over the full width off the valley floor. The area of the incident wave between the second contact point and the triple point is seen to bow out into the downstream flow. The Mach stem of the reflection off the valley floor tends to become less pronounced for the larger valley floor inclination angles. In all the rectangular valleys, a shear layer is present, cascading down the valley wall and then along the valley entrance. The shear layer tends to decrease in size as the valley floor inclination increases. Both prominent reflected shock surfaces are almost conical in nature at close proximity to the valley wall. The triangular valleys show similar reflection patterns as the rectangular valleys. As the incident shock wave initially interacts with the wedge surface only regular reflection occurs. The resulting reflected wave forms the primary reflected surface which flows over into the valley. The reflection changes to Mach reflection as the incident wave interacts with the valley floor. The Mach stem of the reflection off the valley floor increases in characteristic height as one moves from the valley entrance wall to the plane of symmetry. The Mach stem is much smaller for the higher valley floor inclinations. A secondary reflected wave is found underneath the primary reflected surface. The secondary wave is Mach reflection near the plane of symmetry which turns iii to regular reflection closer to the valley wall. The primary and secondary reflected surfaces merge near the plane of symmetry and again along the wedge surface. A shear layer is found to cascade down the valley entrance wall for all geometries, decreasing in strength as the valley inclination angle increases. The parabolic valleys show similar reflection patterns as the triangular valleys. As the incident wave interacts with both the wedge and valley surfaces two reflections occur. The reflection off the wedge surface is regular. As the incident wave flows over into the valley the initial reflection off the valley floor is regular. This regular reflection then turns into Mach reflection the closer one moves to the symmetry plane. The Mach reflection off the valley floor forms a secondary reflected wave underneath the primary reflected wave that is found to flow over into the valley. The primary reflected wave contacts the incident wave at a second contract point found above the triple point. This contact point moves closer to the triple point and eventually along the secondary reflected wave as the incident wave advances downstream. The second contact point at a single time instant is also seen to move closer to the triple point as one moves closer to the plane of symmetry. A shear layer is found cascading down the valley entrance wall. The secondary reflected wave of the Mach reflection off valley floor forms a semi-circular surface which contacts the floor just after the shear layer. The Mach reflection off the valley floor changes to regular reflection as the surface begins to climb up along the valley entrance wall. The conical valleys once again show similar reflection patterns as those found in the other valley geometries. As the incident wave interacts with both the wedge and valley surfaces two reflections occur. Regular reflection occurs off the wedge surface with the resulting primary reflected wave flowing over into the valley. This primary reflected wave contacts the incident shock at a second contact point in the valley. The reflection off the valley floor is regular close to the valley entrance wall changing to Mach reflection nearer the symmetry plane. The reflected wave from the Mach reflection forms the secondary reflected surface found beneath the primary reflected wave. The secondary reflected Mach wave changes to regular reflection as the surface nears the valley wall, with the reflection point travelling along the valley floor until coincident with the valley entrance wall, where it then travels along the entrance wall. The second contact point found on the incident wave is found above the triple point and moves down the incident shock to eventually coincide with the triple point. A weak shear layer is found to cascade down the valley entrance wall. A weak separation also occurs at the entry point of the valley. iv The three hill geometries, triangular, parabolic and conical, all display similar reflection patterns. As the incident wave advances downstream regular reflection occurs off both the wedge and hill surfaces. The reflected waves come together at a point off the surface. At this point a double triple point occurs with two resulting Mach stems. One Mach stem contacts the wedge surface while the other contacts the hill surface. The resulting double Mach stem surface wraps around the base of the hill getting progressively tighter the closer it gets to the incident wave. The only major differences between all three geometries is the shape of the resulting reflected wave off the hill surface (which tends to follow the same geometric shape as the hill) and the distance between the two triple points for the conical and parabolic hills tends to be larger than that found for the triangular hill.
58

Reflektionssamtalets möjligheter och begränsningar : En undersökning om det stöttande reflektionssamtalet som skrivutvecklande metod inom Sfi-undervisning

Lind, Maja January 2010 (has links)
<p>Writing is a critical element for many of the second language learners that I’ve encountered in my work as a Swedish teacher. Therefore, on the basis of Jerome Bruners theories of reflec-tion and learning, was the purpose with this study to examine the scaffolded structured reflec-tion conversation as a method for writing development. Bruner says that the knowledge be-comes deeper when we consciously reflect over it (Arfwedson 1992:110 f).</p><p>I have used a qualitative method where I let five students write a text in Swedish on the subject "application for internship". After that I held a conversation with each of the pupils. By asking them questions I wanted them to reflect on their writing process, and the language and content in their written texts. After this I let the students revise the texts, with the invita-tion to use the thoughts from the conversation.</p><p>By this I wanted to examine to which extent the five reflection conversations led to reflec-tion on the students' own writing, as well as on language and content in the texts. I also wanted to examine how the students changed their texts after the conversations and which factors can be interpreted as being significant for the outcome of the conversations.</p><p>The study has shown that the outcome of the scaffolded structured reflection conversa-tions is very much dependent on the students' respective inputs and focus of the talks. The results indicate that a person who enters the conversation with a focus on developing his/her writing in general is generally more inclined to reflect than a student who enters with a strong focus on the individual task. These results also finds support in earlier theories of reflection.</p><p>In accordance with previous research, this study also demonstrated that it is essential that the reflection is based on the individuals’ circumstances and experiences. I had before the conversations constructed a manual with questions, which I used in all conversations. The results show that only those students who during the conversation were within what Vygotskij calls the zone of proximal development, through my questions got the scaffolding that they needed to reflect.</p>
59

Numerical Determination Of The Transition Boundary Between Regular and Mach Reflection For Planar Shocks Striking Wedges and Cones in Air

Michalagas, Dean Andrew 15 February 2010 (has links)
A numerical investigation of the interaction of a planar shock wave with a rigid wedge and cone in an air-filled shock tube is performed by computing the unsteady flow field of the interaction process. The Euler and Navier-Stokes equations are solved in two dimensions to produce flow solutions for regular and Mach reflections with and without the viscous and thermal boundary layer on the inclined surface. The transition boundary between these two patterns is determined by changing both the shock strength and the angle of the inclined surface so that the simulations are perpendicular to the theoretical transition boundary. The numerically determined boundaries are compared to the theoretical boundaries predicted by two- and three- shock theories and with results obtained from experiments. The results show that the transition boundary between regular and Mach reflection is different not only for wedges and cones but also for inviscid and viscous numerical solutions.
60

Numerical Determination Of The Transition Boundary Between Regular and Mach Reflection For Planar Shocks Striking Wedges and Cones in Air

Michalagas, Dean Andrew 15 February 2010 (has links)
A numerical investigation of the interaction of a planar shock wave with a rigid wedge and cone in an air-filled shock tube is performed by computing the unsteady flow field of the interaction process. The Euler and Navier-Stokes equations are solved in two dimensions to produce flow solutions for regular and Mach reflections with and without the viscous and thermal boundary layer on the inclined surface. The transition boundary between these two patterns is determined by changing both the shock strength and the angle of the inclined surface so that the simulations are perpendicular to the theoretical transition boundary. The numerically determined boundaries are compared to the theoretical boundaries predicted by two- and three- shock theories and with results obtained from experiments. The results show that the transition boundary between regular and Mach reflection is different not only for wedges and cones but also for inviscid and viscous numerical solutions.

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