This thesis presents a design for an Intelligent Educational System to support the teaching of design evaluation in engineering. The design consists of a simple computerbased tool (or 'learning environment') for displaying and manipulating infonnation used in the course of problem solving, with a separate dialogue component capable of discussing aspects of the problem and of the problem solving strategy with the user. Many of the novel features of the design have been incorporated in a prototype system called WOMBAT. The main focus of this research has been on the design of the dialogue component. The design of the dialogue component is based on ideas taken from recent work on rational agency. The dialogue component has expertise in engaging in dialogues which support collaborative problem solving (involving system and user) in domains characterised as justified beliefs. It is capable of negotiating about what to do next and about what beliefs to take into account in problem solving. The system acquires problem-related beliefs by applying a simple plausible reasoning mechanism to a database of possible beliefs. The dialogue proceeds by turn-taking in which the current speaker constructs their chosen utterance (which may consist of several propositions and questions) and explicitly indicates when they have finished. When it is the system's turn to make an utterance, it decides what to say based on its beliefs about the current situation and on the likely utility of the various possible responses which it considers appropriate in the circumstances. Two aspects of the problem solving have been fully implemented. These are the discussion about what criteria a decision should be based on and the discussion about what decision step should be taken next. The system's contributions to the interaction are opportunistic, in the sense that at a dialogue level the system does not try to plan beyond the current utterance, and at a problem solving level it does not plan beyond the next action. The results of a formative evaluation of WOMBAT, in which it was exposed to a number of engineering educators, indicate that it is capable of engaging in a coherent dialogue, and that the dialogue is seen to have a pedagogical purpose. Although the approach of reasoning about the next action opportunistically has not proved adequate at a problem solving level, at a dialogue level it yields good results.

No description available.

The present work is concerned with the advancement of the knowledge of structural optimization in engineering design while focusing on efficient and easy to use ways of setting-up the required automated processes as well as the problems arising from it. Three industry examples are considered. In the first example a software tool that serves as a hands-on decision guidance for many occurring design situations for structured wall PE pipes is developed. In order to avoid licensing fees only public domain software or in-house code are used. It offers the efficient and automated simulation of the ringstiffness test as well as the most common pipe installation scenarios. In addition, an optimization feature is implemented for the design of optimum pipe profiles with regards to the ringstiffness test. In the second example a framework for the optimum design of carbon fibre mountain bike frames is developed. An extensively parameterized and automated simulation model is created that allows for varying tube shapes, paths and laminate ply thicknesses as well as joint locations. For improved efficiency a decomposition approach has been employed that decomposes the original optimization problem into a size optimization sub problem and a shape optimization top level problem. The former is solved by the built-in optimization tool in OptiStruct and the latter by means of surrogate based optimization where each experiment in the DoE is a full size optimization. The third example is concerned with the optimum design of a blade for a novel vertical axis wind turbine. A design approach similar to those with horizontal axes is chosen. The altered design requirements are accounted for by creating a parameterized simulation model and performing size optimization runs for 32 models with different material settings and shear web locations where the model creation process has been automated.

Possible changes in brain metabolites are associated with Motor Neurone Disease (MND). Magnetic Resonance Spectroscopy (MRS) has been performed on the brains of MND patients and control volunteers to acquire signals which contain information about brain metabolites from within the motor cortex area. Discrimination between JvThD and normal groups may help to understand the pathogenic mechanisms in MND and may be useful for monitoring the effects of future trial treatment regimens. The research described in this thesis presents the development of a pattern recognition system based on neural networks to correctly distinguish between motor neurone disease (MND) patients and controls when presented with a nuclear magnetic resonance (NMR) spectrum. The NMR spectra are pre-processed to obtain consistent data, and statistical parameters are extracted and selected from each spectrum. Four statistical neural network classifiers are used to provide information and initial decisions (MND/normal). A neural network is then used to combine these to give a final decision. Experimental results indicate that the system can achieve high performance classification on the spectra, including spectra not seen by the system during training. The experiment was repeated on different training and test sets to validate the method and the repeated design shows that the final system was able to achieve high performance classification. A ifizzy rule-based system teclmique is applied to translate and extract rules encoded in weights of neural network classifiers. The neural networks are translated into a few comprehensible rules to understand how the network performs the final decision.

This thesis describes research in the area of automated industrial inspection using machine vision systems. It is anticipated that the algorithms described will contribute to the design of a machine vision system for the automatic surface inspection of cylindrical pellets. Firstly, the acquisition and segmentation of pellet tray images using area capture is described. Individual pellets are segmented from a pellet tray image by a novel system using the Radon transform coupled with data clustering. Subsequent to the segmentation, the linking of four pellet views depicting the entire circumferential area of the pellet is described along with a simple technique to compensate for intensity variations brought about by imaging the three-dimensional cylindrical surface of the pellet. The image processing techniques of filtering, edge detection, thresholding and morphology are used in the segmentation of grey level pellet defect images. The grey level pellet images are low-pass filtered and binary images formed using edge detection with thresholding. Binary morphology operators are then used in conjunction with a termination condition based on the number of objects in the image to ensure homogenous defect representations. The problem of overlapping defects is addressed, resulting in a second algorithm using the Radon transform coupled with data clustering. Prior to classification salient features are extracted from a set of synthetic binary defect images to form feature vectors. The novel idea of image object classification using 100% fuzzy inference is described, and results are shown to be superior to results obtained by feature space classifiers. The sub-classification of crack defects is carried out using a heuristic classifier, and the parameterisation of pellet defects is described.

The research contained in this thesis provides an investigation into a new method of minimising the perceptual differences when encoding digitised speech. An application of the perceptual criteria is described in the context of a codebook encoding methodology Some of the background studies covered aspects of psychoacoustics, in particular the effects of the human outer, middle and inner ear. Models approximating each region of the ear are utilised and concatenated into a single overall auditory response path model. As the objective of the research is to encode and decode speech waveforms, some study into how speech is produced and the classification of speech sounds is required. From this there is a description of a basic speech production model which is modelled as a digital filter. A review of the main categories for coding schemes that are currently employed is presented along with commonly used coding methods. In particular the codebook coding method is reviewed in sufficient detail to contrast with the new coding method. The development of a new perceptual minimisation criterion which relies on dual application of the auditory response path model on the original and reconstructed speech waveforms is described. In this the ordering of eodebook searches, the frequency spectrum used as the search target, windowing functions with durations and placement are all analysed to determine the optimum encoder design. Also described are a number of prospective gain algorithms which cover both time and frequency domain implementations. A new encoder is constructed which fully integrates the new perceptual criterion into the minimisation of the original and reconstructed speech waveforms. In the minimisation no part of the traditional encoder method is used, however both methods use a similar technique for determining gain factors. Speech derived from both encoders was subjectively assessed by a number of untrained, independent listeners. The results presented show that both methods are comparable but there is a slight preference towards the traditional encoder. A measure of the complexity indicated that the new minimisation method is also more complex than the traditional encoder.

The research contained in this thesis is an investigation into mosaic construction. Mosaic techniques are used to obtain images with a large field of view by assembling a sequence of smaller individual overlapping images. In existing methods of mosaic construction only successive images are aligned. Accumulation of small alignment errors occur, and in the case of the image path returning to a previous position in the mosaic, a significant mismatch between nonconsecutive images will result (looping path problem). A new method for consistently aligning all the images in a mosaic is proposed in this thesis. This is achieved by distribution of the small alignment errors. Each image is allowed to modify its position relative to its neighbour images in the mosaic by a small amount with respect to the computed registration. Two images recorded by a rotating ideal camera are related by the same transformation that relates the camera's sensor plane at the time the images were captured. When two images overlap, the intensity values in both images coincide through the intersection line of the sensor planes. This intersection line has the property that the images can be seamlessly joined through that line. An analogy between the images and the physical world is proposed to solve the looping path problem. The images correspond to rigid objects, and these are linked with forces which pull them towards the right positions with respect to their neighbours. That is, every pair of overlapping images are "hinged" through their corresponding intersection line. Aided by another constraint named the spherical constraint, this network of selforganising images has the ability of distributing itself on the surface of a sphere. As a direct result of the new concepts developed in this research work, spherical mosaics (i.e. mosaics with unlimited horizontal and vertical field of view) can be created.

This paper presents a study of the Computer Aided Design (CAD) needs for the Facilities Engineering Division (PENGD) of NASA Langley Research Center. PENGD currently has many more projects than resources. Government cuts and reductions in personnel promise to make the situation worse. PENGD needs to increase the throughput of its existing staff while also decreasing the product cycle of a project. The existing design scenario with PC based CAD is used as a baseline to evaluate possible improvements and cost savings by implementing workstation based CAD with feature-based solid modeling. A detailed case study is used to illustrate and compare the differences in designing with AutoCAD1 and ProlEngineer. Equivalent hourly engineering rates are calculated for each system based on a four year life cycle. The results of the case study and engineering rates are used to determine the actual cost of designing with both CAD systems. A costlbenefit analysis is used to determine the cost effectiveness of continued use of PC based CAD with complex design projects versus the purchase and integration of workstation based CAD. My findings conclude that projects with any degree of uncertainty benefit from workstation based CAD. Solid modeling provides a mechanism for thorough study which reduces modifications, rework, and schedule delays. The associative database greatly reduces the amount of time required to create and update drawings. As uncertainty increases, the savings from using workstation based CAD over PC based CAD also increases. / Master of Engineering

To compete in today's global economy, organizations are under pressure to improve their product development processes. The engineering design process is an important component of the overall product development process. This research considers the relationship of both social and technical variables to the engineering design process. The theoretical foundation of this research is sociotechnical systems theory. This theory states that optimum performance is achieved by jointly considering the technical and the social subsystems. The application domain of the theory is called macroergonomics. A technical variable considered by this research was engineering design process methodology. Two methodologies were considered: sequential engineering and concurrent engineering. Another technical construct considered by this research was the use of computer-supported cooperative work technology (CSCW) or groupware. The social variable considered by this research was group size. Two sizes were considered: large groups of six people and small groups of three people. This research sought to determine the optimum combination of technical and social variables that would result in highest performance. There were two phases of this research. In the first phase, a laboratory experiment was conducted using 180 engineering and building construction students as subjects. The experiment required that a system be conceived, designed, manufactured, and tested by student teams. The experimental design was a 2 x 2 x 2 factorial, between subjects design with five teams in each cell. In the second phase, the results of the first phase were provided to recognized industry and academic experts for their critique. This two-phased approach facilitated the identification of causal relationships among social and technical variables with higher external validity. In the laboratory experiment, there was no significant difference in performance between concurrent engineering groups and sequential engineering processes. Small groups significantly outperformed large groups in all conditions. CSCW did not significantly improve the performance of large or small groups. Participants in the experiment were equally satisfied with all conditions. The external survey strongly endorsed the superiority of concurrent engineering as compared to sequential engineering. There was no statistically significant optimal combination of variables that resulted in the highest design performance. / Ph. D.

This thesis provides insight into the different aspects of compulsator design for use with railgun systems. Specifically, the design space is explored for passively compensated, permanent magnet iron-core compulsators. Seven design parameters are varied within a compulsator model developed for the Cal Poly Compulsator (CPCPA). The Matlab code for this model is included within the appendix. Efforts were made to compare and validate this compulsator model to published data from existing systems. The compulsator model was found to match closely with discharge pulse length, but resulted in lower values for peak current and projectile velocity by 50% and 30% respectively when compared to published data.