WorldCat Identities

Wright, David James

Works: 3 works in 13 publications in 1 language and 1,780 library holdings
Roles: Author
Classifications: QA614.86, 514.742
Publication Timeline
Most widely held works by David James Wright
Indra's pearls : the vision of Felix Klein by David Mumford( Book )

8 editions published between 2002 and 2008 in English and held by 489 WorldCat member libraries worldwide

"Felix Klein, one of the great nineteenth-century geometers, discovered in mathematics an idea prefigured in Buddhist mythology: the heaven of Indra contained a net of pearls, each of which was reflected in its neighbour, so that the whole Universe was mirrored in each pearl. Klein studied infinitely repeated reflections and was led to forms with multiple co-existing symmetries, each simple in itself, but whose interactions produce fractals on the edge of chaos. For a century these images, which were practically impossible to draw by hand, barely existed outside the imagination of mathematicians. However in the 1980s the authors embarked on the first computer exploration of Klein's vision, and in so doing found further extraordinary images of their own. Join the authors on the path from some basic mathemathical ideas to the simple algorithms that create the delicate fractal filigrees, most of which have never appeared in print before. Beginners can learn to understand what the images mean and follow the step-by-step instructions for writing computer programs that generate them. More advanced readers can see how the images relate to ideas that take them to the forefront of research."--Jacket
Dirichlet series associated with the space of binary cubic forms with coefficients in a number field by David James Wright( )

4 editions published in 1982 in English and Undetermined and held by 4 WorldCat member libraries worldwide

Movement-related cortical potential markers of motor skill learning by David James Wright( Book )

1 edition published in 2012 in English and held by 1 WorldCat member library worldwide

In this thesis the cortical processes involved in motor skill learning were examined. Electroencephalography (EEG) was used to record the movement-related cortical potential (MRCP): an event-related potential reflecting the cortical activity involved in motor planning and preparation, prior to performance of a guitar playing task. A series of five experiments was conducted to investigate how the MRCP may vary depending on a performer's skill level and how it may change with skill learning. In Study 1 a scale-playing task on the guitar, from which it was possible to accurately record the MRCP, was identified. In Study 2, the MRCP was recorded during scale-playing on the guitar from a group of experienced guitarists and a group of non- musicians who had no prior musical training and no experience of playing any musical instrument. Differences in the amplitude and onset times of the MRCP components were compared across groups, with results indicating that the experienced guitarists allocated less cortical activity to planning the performance of the scale than the non-musicians. The purposes of Studies 3, 4, and 5 were to establish the extent to which these between- group differences were the result of training by the experienced guitarists. In Study 3 the effect of short-term practice on movement-related cortical activity was investigated and, contrary to the hypothesis, found an increase in cortical activity involved in movement preparation following practice on the guitar. In Studies 4a and 4b the effect of long-term motor practice on the MRCP was explored. Non-musicians took part in a five and ten week training programme, learning to play the guitar. Study 4a reported a decrease in cortical activity in certain parts of the motor cortex following five weeks of learning to play a scale on the guitar. When the training programme was extended to ten weeks in Study 4b however, an increase in cortical activity was found in certain areas of the motor cortex. Study 4c investigated the effect of a period of de-training on the MRCP in five iv participants. Results from these participants indicated a decrease in MRCP amplitude following training. This reduced amplitude was also found following a five-week period of de-training. Finally, in Study 5, within-session changes in cortical activity were investigated over an extended ten-week learning period. The combined results of Studies 3 and 5 indicate that there may be an increase in both pre- and primary motor cortex activity during the initial phase of motor skill learning, followed by a decrease in motor cortex activity once the performer becomes competent in the task. From the results of these studies, it was concluded that the process of motor skill learning is likely to be more complex than is currently stated in the literature. Rather than a simple linear decrease in the amount of cortical activity involved in motor planning as a result of learning, it is more likely that fluctuations in cortical activity occur at different stages in the learning period, which may, over time, lead to a reduced activity being required during motor preparation
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Audience level: 0.09 (from 0.08 for Indra's pe ... to 0.89 for Dirichlet ...)

Indra's pearls : the vision of Felix Klein
English (12)