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Development and analysis of hierarchical feedforward neural network systems for classification of motor neurone disease based on magnetic resonance spectraRefaee, Mohamed January 2001 (has links)
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.
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Machine vision system developments for industrial inspection applicationsField, Matthew January 1997 (has links)
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.
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Lossy compression of speech using perceptual criteriaO'Donnell, Michael January 1998 (has links)
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.
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Spherical mosaic construction using physical analogy for consistent image alignmentGonzalez, Manuel Guillen January 1999 (has links)
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.
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Variability-Modelling Practices in Industrial Software Product Lines: A Qualitative StudyNair, Divya Karunakaran 06 May 2013 (has links)
Many organizations have transitioned from single-systems development to product-line development with the goal of increasing productivity and facilitating mass customization. Variability modelling is a key activity in software product-line development that deals with the explicit representation of variability using dedicated models. Variability models specify points of variability and their variants in a product line. Although many variability-modelling notations and tools have been designed by researchers and practitioners, very little is known about their usage, actual benefits or challenges. Existing studies mostly describe product-line practices in general, with little focus on variability modelling. We address this gap through a qualitative study on variability-modelling practices in medium- and large-scale companies using two empirical methods: surveys and interviews. We investigated companies' variability-modelling practices and experiences with the aim to gather information on 1) the methods and strategies used to create and manage variability models, 2) the tools and notations used for variability modelling, 3) the perceived values and challenges of variability modelling, and 4) the core characteristics of their variability models. Our results show that variability models are often created by re-engineering existing products into a product line. All of the interviewees and the majority of survey participants indicated that they represent variability using separate variability models rather than annotative approaches. We found that developers use variability models for many purposes, such as the visualization of variabilities, configuration of products, and scoping of products. Although we observed that high degree of heterogeneity exists in the variability-modelling notations and tools used by organizations, feature-based notations and tools are the most common. We saw huge differences in the sizes of variability models and their contents, which indicate that variability models can have different use cases depending on the organization. Most of our study participants reported complexity challenges that were related mainly to the visualization and evolution of variability models, and dependency management. In addition, reports from interviews suggest that product-line adoption and variability modelling have forced developers to think in terms of a product-line scenario rather than a product-based scenario.
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The integration of rapid prototyping within industrial design practiceEvans, Mark January 2002 (has links)
Three-dimensional appearance models represent an essential outcome of industrial design practice, facilitating the origination, evaluation and specification of exterior form. As manufacturers face increasing pressure to reduce time scales for new product development, the production of such models using conventional fabrication techniques must be appraised. As a means of economically translating digital geometry into one-off components, rapid prototyping has the potential to contribute towards a reduction in lead times for the production of appearance models. The objective of this research is to propose a methodological approach for the effective integration of rapid prototyping within industrial design practice. The field and practice of industrial design is defined, the technology of rapid prototyping discussed, and their integration proposed through a draft computer-aided industrial design/rapid prototyping (CAID/RP) methodological approach. This is exposed to practitioner feedback, modified, and employed as a revised CAID/RP methodological approach during the industrial design of a nylon line trimmer. The product outcome is used to compare and contrast the production of an appearance model via rapid prototyping, an appearance prototype via rapid prototyping, and an appearance model via conventional fabrication techniques. Two issues arise from the use of the revised CAID/RP methodological approach: the production of stl files and the lack of physical interaction with product form. In addition, the emergence of rapid prototype sketch modelling systems following the line trimmer case study provides an opportunity for further enhancement. A strategy for the resolution of these issues is proposed, and their effectiveness evaluated through additional case studies. The resulting CAID/RP methodological approach is subject to validation through practitioner interviews and a normalised rating/weighting method. The positive feedback acknowledges the significance of the CAID/RP methodological approach through a reduction in product development lead times and enhancement of professional practice. The project makes a contribution to new knowledge and understanding in the area of professional practice through the definition and validation of operational paradigmatic change.
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Variability-Modelling Practices in Industrial Software Product Lines: A Qualitative StudyNair, Divya Karunakaran 06 May 2013 (has links)
Many organizations have transitioned from single-systems development to product-line development with the goal of increasing productivity and facilitating mass customization. Variability modelling is a key activity in software product-line development that deals with the explicit representation of variability using dedicated models. Variability models specify points of variability and their variants in a product line. Although many variability-modelling notations and tools have been designed by researchers and practitioners, very little is known about their usage, actual benefits or challenges. Existing studies mostly describe product-line practices in general, with little focus on variability modelling. We address this gap through a qualitative study on variability-modelling practices in medium- and large-scale companies using two empirical methods: surveys and interviews. We investigated companies' variability-modelling practices and experiences with the aim to gather information on 1) the methods and strategies used to create and manage variability models, 2) the tools and notations used for variability modelling, 3) the perceived values and challenges of variability modelling, and 4) the core characteristics of their variability models. Our results show that variability models are often created by re-engineering existing products into a product line. All of the interviewees and the majority of survey participants indicated that they represent variability using separate variability models rather than annotative approaches. We found that developers use variability models for many purposes, such as the visualization of variabilities, configuration of products, and scoping of products. Although we observed that high degree of heterogeneity exists in the variability-modelling notations and tools used by organizations, feature-based notations and tools are the most common. We saw huge differences in the sizes of variability models and their contents, which indicate that variability models can have different use cases depending on the organization. Most of our study participants reported complexity challenges that were related mainly to the visualization and evolution of variability models, and dependency management. In addition, reports from interviews suggest that product-line adoption and variability modelling have forced developers to think in terms of a product-line scenario rather than a product-based scenario.
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The scope for the application of continuous improvement to the process of new product developmentCaffyn, Sarah Jane January 1998 (has links)
This is an investigation into the scope for applying continuous improvement (CI) to the process of new product development (NPD). The thesis makes two main contributions to knowledge. Firstly, it brings together the fields of continuous improvement of processes and NPD, which both have their own literature and research activity but have hitherto remained somewhat separated from each other. Secondly, it develops and tests an analytical model to support the implementation of CI within NPD.
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Pulse and rhythm : exploring the value of repetitive motion as an element of designYoshimoto, Hideki January 2015 (has links)
With this thesis I want to share my exploration of pulse and rhythm as elements of design. I locate my research on the meeting point of two different contexts: one is the expansion of kinetic art into design projects, resulting in aesthetic use of motion playing wider roles in design, and the other is the expansion, in relation to technological development, of the value of pulse as a design element. My hypothesis is that the value of pulse as an element of design can be heightened by acquiring the aesthetic use of repetitive motion seen in kinetic art, forging emotional communication with viewers/users. The mission of this research is to demonstrate this argument through practice, collecting working ideas and methods. I propose a model of pulse which can be used as a tool to reflect on projects from a new perspective. To forge a workable focus for the research, I articulate a definition of Japanese aesthetics and deploy related criteria of design. My exploration covers three topics - single pulse, pulse synchronisation, and pulse interference. Several ideas and methods were tested across eight projects in total, related to theories from various fields including biology, physiology, psychology, philosophy, mathematics and physics, and inspired by art and design practice. The insights gained from the projects allowed me to expand the scope of the exploration from pulse to rhythm, and I also reflect on my work from this perspective, distinguishing rhythm from pulse. Furthermore, I conducted an interview-based study to look into rhythm inferred from non-pulsing motions, and the insights from the interviews are presented in the thesis with an additional discussion. The output of the research takes two forms: recommendations, as a simpliflied and generalised summary of my findings, and case studies (projects), as a concrete source of inspiration for the reader's own creations. By thus interweaving the practical and theoretical knowledge gained in the research, I believe this work provides a useful contribution to the field of design.
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Laser shaping : a method for controlling the elastic behaviour of stretch fabrics for a targeted and graduated compressive effect on the bodyPaine, Helen January 2016 (has links)
This research was commissioned and funded by The Welding Institute (TWI). The Welding Institute are a global research and development facility specialising in the joining of materials for industrial applications. The purpose of this research was to develop capability in textiles joining, particularly ultrasonic and laser welding technologies, which is relatively new to TWI. The appointed researcher adopted a ‘multi-strategy’ (Cresswell 2009) approach to the research; encompassing methods that were both familiar and unfamiliar to those usually adopted by TWI employees and researchers, whom mostly come from engineering and scientific backgrounds. The research was primarily undertaken with the adoption of a ‘craft-design’ approach that uses material investigation to explore and uncover interesting leads for investigation, which was the familiar approach of the researcher coming from a background in textile design. Material studies were carried out inquisitively without the formation of a particular hypothesis and insights were discussed with industry to identify potential commercial and functional application opportunities. Following the identification of an interest in welding stretchy fabrics Speedo agreed to become the main industry partner for the research, providing materials, access to testing equipment and validation of commercial opportunities for material samples relative to their application. The main hypothesis for the research Laser melted patterns can be used to control the elastic behaviour of stretchy textiles to have a targeted and variable compressive effect on the body developed through discussion with Speedo in response to material samples produced using transmission laser welding equipment. A predominant scientific approach was adopted during the second phase of the research to quantify and control this effect: to demonstrate repeatability and test it both on fabric and the body. Methods that were unfamiliar to the researcher prior to this research such as mechanical testing and microscopic analysis were employed. Selection of either a ‘craft design’ or ‘scientific’ approach was made pragmatically in response to the research as it developed. Through a retrospective analysis of applied methods throughout the research trajectory it has been possible to define this particular ‘multi-strategy’ project as a ‘sequential exploratory’ design (Cresswell 2009), whereby periods of subjective investigation are followed by empirical testing. The main process that has been developed by this research is a decorative method of controlling the elastic behaviour of stretchy fabrics using transmission laser welding equipment for a controlled and variable compressive effect on the body. Compression fabrics are used widely within the medical, lingerie and sportswear fields to apply pressure to the body either for an aesthetic or functional advantage. In swimwear, compression fabrics are applied to streamline the silhouette and minimise drag resistance. The technique developed by this research makes a contribution to knowledge within the field of laser processing of textiles, specifically within the field of transmission laser welding, and within the field of compression apparel. In the field of transmission laser welding a new functional capability for all-over surface patterns has been demonstrated. In the field of compression apparel a new decorative method for achieving an increasingly variable compressive effect for a smoother transition between different zones of stretch has been achieved. N.B. All redacted information throughout this thesis is confidential to Speedo.
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