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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.
191

A Case Study of High-School Student Self-Regulation Responses to Design Failure

Andrew M. Jackson (5929802) 16 January 2019 (has links)
<div>Although design is part of everyday experience, increased proficiency in managing and reflecting while designing signify greater proficiency as a designer. This capacity for regulation in design is crucial for learning, including from failure experiences, while designing. Failure and iteration are integral parts of design, with potential cognitive and psychological ramifications. On the one hand, failure can be framed as a learning experience that interrupts thinking and evokes reflection. On the other hand, it can be detrimental for confidence and motivation or derail the design process. Based on similarities between design and self-regulation, I articulate a framework whereby responses to failure might be regulated by beginning designers. Then, this case study applies the framework to describe the experiences and perspectives of beginning designers as they work and fail, illuminating issues of failure in design and the extent of their self-regulation.</div><div><br></div><div>The in situ design processes of four teams was examined to describe self-regulation strategies among student designers. Analysis was conducted with two methods: linkography and typological thematic analysis. Linkography, based on think-aloud data, provided a visual representation of the design process and tools to identify reflection, planning, and critical moments in the design process. Typological analysis, based on think-aloud data, follow-up interviews, and design journals, was used to investigate specific strategies of self-regulation. The complementary methods contribute to understanding beginning designers’ self-regulation from multiple perspectives.</div><div><br></div><div>Results portray varied trajectories in design, ranging from repeated failure and determination to fleeting success and satisfaction. Class structures emerge in designers’ patterns of planning and reflection. These highlight the contextualized and evolutionary nature of design and self-regulation. Furthermore, linkographic evidence showed a beginning sense-making process, followed by oscillating phases of forward and backward thinking, to various degrees. Moments of testing, both successes and failure, were critically connected in the design process.</div><div><br></div><div>Thematic analysis identified 10 themes, aligning with the self-regulatory phases of forethought, performance, and reflection. The themes highlight how regulation in forethought is used to shape performance based on past iterations; meanwhile, the identification and attribution of failures relays information on how, and whether to iterate. Collectively, thematic findings reinforce the cyclical nature of design and self-regulation.</div><div><br></div><div>Design and self-regulation are compatible ways of thinking; for designers, the juxtaposition of these concepts may be useful to inform patterns of navigating the problem-solving process. For educators, the imposition of classroom structures in design and self-regulatory thinking draws attention to instructional design and assessment for supporting student thinking. And for researchers of design or self-regulation, these methods can give confidence for further exploration.</div>
192

The application of practical geometry and the golden ratio in product design

Koh, Hyo Jin January 2015 (has links)
There have been numerous researchers who, over the years, have explored the relationship between the golden ratio and how it relates to the human perception of beauty. Although the golden proportion is one of the aesthetic characteristics contained in many masterpieces of art and design, it is still largely thought of as little more than an aesthetic guideline, that is, if indeed it is even being considered at all. This thesis asserts that golden proportion and practical geometric knowledge can be used as an extremely effective means of codifying the creative process, inspiring and influencing creative design decisions. This thesis is concerned with examining the application of practical geometric knowledge as an integral part of the design process. It also documents the development of the author's geometric refinement tools and discusses the results of their performance in testing by scrutinizing the opinions of design students and professional designers who both had their designs modified by the author's refinement tools. The relationship between geometric knowledge embedded in design classics and bestselling items was also examined. This thesis describes a mixed methods approach with multiple analyses, from which qualitative and quantitative data (about the implementation of applying geometric knowledge) was gathered via two geometry workshops, interviews with the professional designers, as well as an analysis of visual materials consisting of two hundred selected design examples. Based upon the process of employing geometric knowledge and its experiments, the thesis presents a descriptive analysis of the data to test theoretical propositions and draw conclusions about the value of applying practical geometry as design knowledge and as a practical tool for a design in the modern context. The significance of this thesis is that it elucidates upon the use of the golden ratio, and practical geometry as a practical design refinement tool, with the ability to transform the perception of practical geometry from being merely an aesthetic guideline which appears in masterpieces from the past, to a directly applicable practical design technique. The main contribution this thesis makes to the field of design practice is that it attempts to further understand the results achieved by codifying designing styles and design decisions, a process which can be described as objective rational knowledge in practice. This thesis frames individual design participants' perspectives of the golden ratio and the relationship between modern designs and the masterpieces of history. Thereby, hopefully providing a historical perspective and a modern context for the golden ratio. Further to that, it is the author's hope that this work will provide inspiration to today's designers, motivating them to begin implementing practical geometry into their designs and in the future generations of design education to come.
193

The prediction and management of the variability of manufacturing operations

Steele, Clint, n/a January 2005 (has links)
Aim: To investigate methods that can be used to predict and manage the effects of manufacturing variability on product quality during the design process. Methodology: The preliminary investigation is a review and analysis of probabilistic methods and quality metrics. Based on this analysis, convenient robustification methods are developed. In addition, the nature of the flow of variability in a system is considered. This is then used to ascertain the information needed for an input variable when predicting the quality of a proposed design. The second, and major, part of the investigation is a case-by-case analysis of a collection of manufacturing operations and material properties. Each is initially analysed from first principles. On completion, the fundamental causes of variability of the key characteristic(s) are identified. Where possible, the expected variability for each of those characteristics has been determined. Where this determination was not possible, qualitative conclusions about the variability are made instead. In each case, findings on the prediction and management of manufacturing variability are made.
194

An interactive monochrome and colour graphics display system

Davis, Andrew Lennox. January 1978 (has links) (PDF)
Typescript (photocopy)
195

Structural Behaviour of Post Tensioned Concrete Structures : Flat Slab. Slabs on Ground

Trygstad, Steinar January 2001 (has links)
<p>In this investigation strength and structural behaviour of prestressed concrete is studied with one full scale test of one flat slab, 16000 mm x 19000 mm, and three slabs on ground each 4000 mm x 4000 mm with thickness 150 mm. The flat slab was constructed and tested in Aalesund. This slab has nine circular columns as support, each with diameter 450 mm. Thickness of this test slab was 230 mm and there were two spans in each direction, 2 x 9000 mm in x-direction and 2 x 7500 mm in y-direction from centre to centre column. The slab was reinforced with twenty tendons in the middle column strip in y-direction and eight tendons in both outer column strips. In x-direction tendons were distributed with 340 mm distance. There were also ordinary reinforcement bars in the slab. Strain gauges were welded to this reinforcement, which together with the deflection measurements gives a good indication of deformation and strains in the structure.</p><p>At a live load of 6.5 kN/m<sup>2</sup> shear failure around the central column occurred: The shear capacity calculated after NS 3473 and EuroCode2 was passed with 58 and 69 %, respectively. Time dependent and non-linear FE analyses were performed with the program system DIANA. Although calculated and measured results partly agree well, the test show that this type of structure is complicated to analyse by non-linear FEM.</p><p>Prestressed slabs on ground have no tradition in Norway. In this test one reinforced and two prestressed slabs on ground were tested and compared to give a basis for a better solution for slabs on ground. This test was done in the laboratory at Norwegian University of Science and Technology in Trondheim. The first slab is reinforced with 8 mm bars in both directions distributed at a distance of 150 mm in top and bottom. Slab two and three are prestressed with 100 mm<sup>2</sup> tendons located in the middle of slab thickness, and distributed at a distance of 630 mm in slab two and 930 mm in slab three. Strain gauges were glued to the reinforcement in slab one and at top and bottom surface of all three slabs. In slab two and three there were four load cells on the tendons.</p><p>Each slab were loaded with three different load cases, in the centre of slab, at the edge and finally in the corner. This test shows that stiffness of sub-base is one of the most important parameters when calculating slabs on ground. Deflection and crack load level depends of this parameter. Since the finish of slabs on ground is important, it can be more interesting to find the load level when cracks start, than deflection for the slab. It is shown in this test that crack load level was higher in prestressed slabs than in reinforced slab. There was no crack in the top surface with load in the centre, but strain gauges in the bottom surface indicate that crack starts at a load of 28 kN in the reinforced slab, and 45 kN in the prestressed slabs. Load at the edge give a crack load of 30 kN in reinforced slab, 45 kN and 60 kN in prestressed slabs. The last load case gives crack load of 30 kN in reinforced slab, 107 kN and 75 kN in prestressed slabs. As for the flat slab, FE analyses were performed for all of the three slabs on ground, and analyses shows that a good understanding of parameters like stiffness of sub-base and tension softening model, is needed for correct result of the analyses.</p>
196

Capacity Assessment of Titanium Pipes Subjected to Bending and External Pressure

Bjørset, Arve January 2000 (has links)
<p>Exploration for oil and gas is moving towards deeper waters. Steel has been the most common riser material. Related to deep water concepts titanium has become an alternative to steel for these applications.</p><p>Several codes exist today for predicting collapse loads for marine pipes. However, the capacity formulas are developed for steel. If the formulas are applied directly to titanium several parameter uncertainties will be unknown. Ideally, extensive model testing of titanium pipes is required. This thesis discusses and investigates utilisation of experimental material test data and a supplementary numerical approach based on finite element analysis. The relationship between material model parameters as input to the analysis and the collapse capacity is investigated by performing a series of nonlinear FEM analyses.</p><p>Statistical models for the input material model parameters are established based on tests on small specimens cut from titanium pipes. These models are subsequently combined with results from the FEM analyses by application of response surface methods. As output from the analysis, the probability distributions of the pipe capacity with respect to local buckling/collapse are obtained.</p><p>Finally, the data from the nonlinear finite element analyses are compared to a relevant design code. Suggestions for a possible basis for design formulas to check for the local collapse capacity of deep water titanium risers are provided.</p>
197

Capacity Assessment of Titanium Pipes Subjected to Bending and External Pressure

Bjørset, Arve January 2000 (has links)
Exploration for oil and gas is moving towards deeper waters. Steel has been the most common riser material. Related to deep water concepts titanium has become an alternative to steel for these applications. Several codes exist today for predicting collapse loads for marine pipes. However, the capacity formulas are developed for steel. If the formulas are applied directly to titanium several parameter uncertainties will be unknown. Ideally, extensive model testing of titanium pipes is required. This thesis discusses and investigates utilisation of experimental material test data and a supplementary numerical approach based on finite element analysis. The relationship between material model parameters as input to the analysis and the collapse capacity is investigated by performing a series of nonlinear FEM analyses. Statistical models for the input material model parameters are established based on tests on small specimens cut from titanium pipes. These models are subsequently combined with results from the FEM analyses by application of response surface methods. As output from the analysis, the probability distributions of the pipe capacity with respect to local buckling/collapse are obtained. Finally, the data from the nonlinear finite element analyses are compared to a relevant design code. Suggestions for a possible basis for design formulas to check for the local collapse capacity of deep water titanium risers are provided.
198

Structural Behaviour of Post Tensioned Concrete Structures : Flat Slab. Slabs on Ground

Trygstad, Steinar January 2001 (has links)
In this investigation strength and structural behaviour of prestressed concrete is studied with one full scale test of one flat slab, 16000 mm x 19000 mm, and three slabs on ground each 4000 mm x 4000 mm with thickness 150 mm. The flat slab was constructed and tested in Aalesund. This slab has nine circular columns as support, each with diameter 450 mm. Thickness of this test slab was 230 mm and there were two spans in each direction, 2 x 9000 mm in x-direction and 2 x 7500 mm in y-direction from centre to centre column. The slab was reinforced with twenty tendons in the middle column strip in y-direction and eight tendons in both outer column strips. In x-direction tendons were distributed with 340 mm distance. There were also ordinary reinforcement bars in the slab. Strain gauges were welded to this reinforcement, which together with the deflection measurements gives a good indication of deformation and strains in the structure. At a live load of 6.5 kN/m2 shear failure around the central column occurred: The shear capacity calculated after NS 3473 and EuroCode2 was passed with 58 and 69 %, respectively. Time dependent and non-linear FE analyses were performed with the program system DIANA. Although calculated and measured results partly agree well, the test show that this type of structure is complicated to analyse by non-linear FEM. Prestressed slabs on ground have no tradition in Norway. In this test one reinforced and two prestressed slabs on ground were tested and compared to give a basis for a better solution for slabs on ground. This test was done in the laboratory at Norwegian University of Science and Technology in Trondheim. The first slab is reinforced with 8 mm bars in both directions distributed at a distance of 150 mm in top and bottom. Slab two and three are prestressed with 100 mm2 tendons located in the middle of slab thickness, and distributed at a distance of 630 mm in slab two and 930 mm in slab three. Strain gauges were glued to the reinforcement in slab one and at top and bottom surface of all three slabs. In slab two and three there were four load cells on the tendons. Each slab were loaded with three different load cases, in the centre of slab, at the edge and finally in the corner. This test shows that stiffness of sub-base is one of the most important parameters when calculating slabs on ground. Deflection and crack load level depends of this parameter. Since the finish of slabs on ground is important, it can be more interesting to find the load level when cracks start, than deflection for the slab. It is shown in this test that crack load level was higher in prestressed slabs than in reinforced slab. There was no crack in the top surface with load in the centre, but strain gauges in the bottom surface indicate that crack starts at a load of 28 kN in the reinforced slab, and 45 kN in the prestressed slabs. Load at the edge give a crack load of 30 kN in reinforced slab, 45 kN and 60 kN in prestressed slabs. The last load case gives crack load of 30 kN in reinforced slab, 107 kN and 75 kN in prestressed slabs. As for the flat slab, FE analyses were performed for all of the three slabs on ground, and analyses shows that a good understanding of parameters like stiffness of sub-base and tension softening model, is needed for correct result of the analyses.
199

Machine learning in engineering : techniques to speed up numerical optimization

Cerbone, G. (Giuseppe) 13 April 1992 (has links)
Many important application problems in engineering can be formalized as nonlinear optimization tasks. However, numerical methods for solving such problems are brittle and do not scale well. For example, these methods depend critically on choosing a good starting point from which to perform the optimization search. In high-dimensional spaces, numerical methods have difficulty finding solutions that are even locally optimal. The objective of this thesis is to demonstrate how machine learning techniques can improve the performance of numerical optimizers and facilitate optimization in engineering design. The machine learning methods have been tested in the domain of 2-dimensional structural design, where the goal is to find a truss of minimum weight that bears a set of fixed loads. Trusses are constructed from pure tension and pure compression members. The difference in the load-bearing properties of tension and compression members causes the gradient of the objective function to be discontinuous, and this prevents the application of powerful gradient-based optimization algorithms in this domain. In this thesis, the approach to numerical optimization is to find ways of transforming the initial problem into a selected set of subproblems where efficient, gradient-based algorithms can be applied. This is achieved by a three-step "compilation" process. The first step is to apply speedup learning techniques to partition the overall optimization task into sub-problems for which the gradient is continuous. Then, the second step is to further simplify each sub-problem by using inductive learning techniques to identify regularities and exploit them to reduce the number of independent variables. Unfortunately, these first two steps have the potential to produce an exponential number of sub-problems. Hence, in the third step, selection rules are derived to identify those sub-problems that are most likely to contain the global optimum. The numerical optimization procedures are only applied to these selected sub-problems. To identify good sub-problems, a novel ID3-like inductive learning algorithm called UTILITYID3 is applied to a collection of training examples to discover selection rules. These rules analyze the problem statement and identify a small number of sub-problems (typically 3) that are likely to contain the global optimum. In the domain of 2-dimensional structural design, the combination of these three steps yields a 6-fold speedup in the time required to find an optimal solution. Furthermore, it turns out that this method is less reliant on a good starting point for optimization. The methods developed in this problem show promise of being applied to a wide range of numerical optimization problems in engineering design. / Graduation date: 1992
200

Developing Biomimetic Design Principles for the Highly Optimized and Robust Design of Products and Their Components

Wadia, Anosh Porus 2011 August 1900 (has links)
Engineering design methods focus on developing products that are innovative, robust, and multi-functional. In this context, the term robust refers to a product's ability to accomplish successfully its predetermined functions. Owing to the abundance of optimized and robust biological systems, engineering designers are now looking to nature for inspiration. Researchers believe that biomimetic or bio-inspired engineering systems can leverage the principles, mechanisms, processes, strategies, and/or morphologies of nature's successful designs. Unfortunately, two important problems associated with biomimetic design are a designer's limited knowledge of biology and the difference in biological and engineering terminologies. This research developed a new design tool that addresses these problems and proposes to help engineering designers develop candidate bio-inspired products or solutions. A methodology that helps users infer or extract biomimetic design principles from a given natural system or biomimetic product pair is described in this thesis. The method incorporates and integrates five existing design tools and theories to comprehensively investigate a given natural system or biomimetic product. Subsequently, this method is used to extract biomimetic design principles from 23 biomimetic products and natural systems. It is proposed that these principles have the potential to inspire ideas for candidate biomimetic products that are novel, innovative, and robust. The principle extraction methodology and the identified principles are validated using two separate case studies and a detailed analysis using the validation square framework. In the first case study, two students and the author use the principle extraction methodology to extract characteristics from a natural system and a biomimetic product pair. Results from this case study showed that the methodology effectively and repeatedly identifies system characteristics that exemplify inherent biomimetic design principles. In the second case study, the developed biomimetic design principles are used to inspire a solution for an engineering design problem. The resulting solution and its evaluation show that the design's achieved usefulness is linked to applying the biomimetic design principles. Similar to the TRIZ principles, the biomimetic design principles can inspire ideas for solutions to a given problem. The key difference is that designers using TRIZ leverage the solution strategies of engineering patents, while designers using the biomimetic design principles leverage nature’s solution strategies. The biomimetic design principles are compared to TRIZ and the BioTRIZ matrix.

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