title: Determining progression in glaucoma using visual fields

authors: Turpin, Andrew

subjects: computer science

abstract: The standardized visual field assessment, which measures visual function in 76 locations of the central visual area, is an important diagnostic tool in the treatment of the eye disease glaucoma. It helps determine whether the disease is stable or progressing towards blindness, with important implications for treatment. Automatic techniques to classify patients based on this assessment have had limited success, primarily due to the high variability of individual visual field measurements. 
The purpose of this paper is to describe the problem of visual field classification to the data mining community, and assess the success of data mining techniques on it. Preliminary results show that machine learning methods rival existing techniques for predicting whether glaucoma is progressing—though we have not yet been able to demonstrate improvements that are statistically significant. It is likely that further improvement is possible, and we encourage others to work on this important practical data mining problem.

text: Determining progression in glaucoma using visual fields The standardized visual field assessment, which measures visual function in 76 locations of the central visual area, is an important diagnostic tool in the treatment of the eye disease glaucoma. It helps determine whether the disease is stable or progressing towards blindness, with important implications for treatment. Automatic techniques to classify patients based on this assessment have had limited success, primarily due to the high variability of individual visual field measurements. 
The purpose of this paper is to describe the problem of visual field classification to the data mining community, and assess the success of data mining techniques on it. Preliminary results show that machine learning methods rival existing techniques for predicting whether glaucoma is progressing—though we have not yet been able to demonstrate improvements that are statistically significant. It is likely that further improvement is possible, and we encourage others to work on this important practical data mining problem.

year: 2001

title: Development and Characterisation of Plasmonic Devices for Sensing Applications

authors: Sedoglavich, Nemanya

subjects: Plasmonic

abstract: In recent years, discoveries and advances that utilise nano-scale (10^-9m) structures and associated phenomena have led to a number of entirely new areas of research in the fields of physics, chemistry, biology, and materials science. The photonic field of plasmonics is the study of light interaction with nanometer-scaled metal-dielectric features, which gives rise to a variety of phenomena, including surface plasmon resonance, localised surface plasmon resonance, and metal enhanced fluorescence. The focus of this thesis is on the development and characterisation of nanophotonic devices, which utilise plasmonic phenomena and have potential for sensor applications.
During the course of this research a surface plasmon resonance analysis platform was devised, which utilises the gold grating of commercially available compact disks as the sensing substrate. This measurement method offers a high resolution refractive index analysis of gases and surface chemistry and is capable of analysing a large number of samples by scanning over the entire disk surface. The system implements a method of phase-polarisation contrast to improve the sensing performance. It enhances signal detection through redistributing the residual p-polarised waves, which have been strongly absorbed by the surface plasmon resonance substrate/sensor. This effectively lowers the reflected light intensity at the surface plasmon resonance minimum. The scheme results in the deepening of the intensity minimum to below 3.5% reflection and the enhancement of resonance to non-resonance contrast by up to 14 times, and thereby increasing sensitivity.
A range of new nanophotonic structures have been modelled, developed, fabricated, and characterised, which we call wavelength and polarisation selective polariton generators (SPGs). These polarisation-sensitive structures combine a tuneable plasmon resonator and a subwavelength aperture to selectively generate and transmit polaritons of a desired wavelength through a central nanohole. Individual SPGs permit modulation of transmission intensity, with calculated enhanced optical transmission (ratio of output to input flux) of up to 10 and up to 4-fold measured amplitude modulation. The paired SPGs gave rise to multiple spectrally discrete transmission peaks which, when modulated, provide a multi-state operation in a single device. The measured amplitude modulation was up to 10-fold. For the linearly continuous SPG, by controlling the polarisation as a tuning variable, it selectively generated and transported polaritons of a desired wavelength. It exhibited a spectral shift of 40 nm over the full range of polarisation angles. The modelled enhanced optical transmission was calculated to be up to 17.2. An instrument was developed for measuring and characterising light transmission through single nanoholes, nanohole arrays, and other complex structures. The operational characteristics of these elements show close agreement between model predictions and experimental data. It also demonstrates new designs of plasmonic structures which utilise selective behaviour based on the polarisation of incident light.

text: Development and Characterisation of Plasmonic Devices for Sensing Applications In recent years, discoveries and advances that utilise nano-scale (10^-9m) structures and associated phenomena have led to a number of entirely new areas of research in the fields of physics, chemistry, biology, and materials science. The photonic field of plasmonics is the study of light interaction with nanometer-scaled metal-dielectric features, which gives rise to a variety of phenomena, including surface plasmon resonance, localised surface plasmon resonance, and metal enhanced fluorescence. The focus of this thesis is on the development and characterisation of nanophotonic devices, which utilise plasmonic phenomena and have potential for sensor applications.
During the course of this research a surface plasmon resonance analysis platform was devised, which utilises the gold grating of commercially available compact disks as the sensing substrate. This measurement method offers a high resolution refractive index analysis of gases and surface chemistry and is capable of analysing a large number of samples by scanning over the entire disk surface. The system implements a method of phase-polarisation contrast to improve the sensing performance. It enhances signal detection through redistributing the residual p-polarised waves, which have been strongly absorbed by the surface plasmon resonance substrate/sensor. This effectively lowers the reflected light intensity at the surface plasmon resonance minimum. The scheme results in the deepening of the intensity minimum to below 3.5% reflection and the enhancement of resonance to non-resonance contrast by up to 14 times, and thereby increasing sensitivity.
A range of new nanophotonic structures have been modelled, developed, fabricated, and characterised, which we call wavelength and polarisation selective polariton generators (SPGs). These polarisation-sensitive structures combine a tuneable plasmon resonator and a subwavelength aperture to selectively generate and transmit polaritons of a desired wavelength through a central nanohole. Individual SPGs permit modulation of transmission intensity, with calculated enhanced optical transmission (ratio of output to input flux) of up to 10 and up to 4-fold measured amplitude modulation. The paired SPGs gave rise to multiple spectrally discrete transmission peaks which, when modulated, provide a multi-state operation in a single device. The measured amplitude modulation was up to 10-fold. For the linearly continuous SPG, by controlling the polarisation as a tuning variable, it selectively generated and transported polaritons of a desired wavelength. It exhibited a spectral shift of 40 nm over the full range of polarisation angles. The modelled enhanced optical transmission was calculated to be up to 17.2. An instrument was developed for measuring and characterising light transmission through single nanoholes, nanohole arrays, and other complex structures. The operational characteristics of these elements show close agreement between model predictions and experimental data. It also demonstrates new designs of plasmonic structures which utilise selective behaviour based on the polarisation of incident light.

year: 2009

title: 'Entitled to a History': The World of Alice Tawhai's Short Stories and the Maori Literary Tradition

authors: Modlik, Kimberley

subjects: Alice Tawhai

abstract: New Zealand short story writer Alice Tawhai is one of the latest additions to the Maori literary tradition. Her three collections of short stories, Festival of Miracles, Luminous and Dark Jelly, deal with issues not entirely unique to New Zealand – from gang life, to domestic violence, to drug and alcohol abuse – and take as their primary subject an alienated, marginalized and disenfranchised underclass. This means she is likely to be read as speaking solely for the Maori experience.  This thesis will revise this misconception, which in effect ghettoizes or marginalizes Tawhai’s work.

Influential women writers of the Maori literary tradition, such as J. C. Sturm, Patricia Grace and Keri Hulme, have taken a particular interest in the long legacy of colonialism in New Zealand, especially of the impact of that legacy on Maori women. This thesis demonstrates that while Tawhai’s work engages with these familiar notions, her gaze is not limited to these issues. This thesis therefore places Tawhai’s work within that tradition and matrilineal genealogy before going on to show how she moves the paradigm beyond the usual grievances of biculturalism and colonialism, orienting her work instead around the increasingly multicultural experience of contemporary life in New Zealand.

The first section of this thesis will establish a platform for reading Tawhai in regards to her literary legacy and in the context of contemporary thinking, drawing on cultural theorist Stuart Hall and his theory on identity formation and identity politics as well as indigenous writings experts Patrick Evans and Chadwick Allen. This thesis will then move into its second section, which is an analysis of some of the overarching themes that can be found in the short stories of Tawhai’s literary foremothers, Sturm, Grace and Hulme. These include, for example, racism and discrimination, loss of ancestral lands, problems to do with urbanization and family violence.

The third and final section of this thesis will then consider Tawhai’s representation of contemporary experience, taking a particular interest in her portrayals of contemporary multicultural ethnic identities as well as the flexible and provisional nature of gendered and sexual identities today. The final subsection will then analyze her representations of the new family and social structures that may have replaced the traditional family model.

Through a close reading of her short stories and an appreciation of the legacy that she bears, this thesis will show how Tawhai’s work is a larger lens of contemporary New Zealand society as well as a significant addition to the Maori literary tradition.

text: 'Entitled to a History': The World of Alice Tawhai's Short Stories and the Maori Literary Tradition New Zealand short story writer Alice Tawhai is one of the latest additions to the Maori literary tradition. Her three collections of short stories, Festival of Miracles, Luminous and Dark Jelly, deal with issues not entirely unique to New Zealand – from gang life, to domestic violence, to drug and alcohol abuse – and take as their primary subject an alienated, marginalized and disenfranchised underclass. This means she is likely to be read as speaking solely for the Maori experience.  This thesis will revise this misconception, which in effect ghettoizes or marginalizes Tawhai’s work.

Influential women writers of the Maori literary tradition, such as J. C. Sturm, Patricia Grace and Keri Hulme, have taken a particular interest in the long legacy of colonialism in New Zealand, especially of the impact of that legacy on Maori women. This thesis demonstrates that while Tawhai’s work engages with these familiar notions, her gaze is not limited to these issues. This thesis therefore places Tawhai’s work within that tradition and matrilineal genealogy before going on to show how she moves the paradigm beyond the usual grievances of biculturalism and colonialism, orienting her work instead around the increasingly multicultural experience of contemporary life in New Zealand.

The first section of this thesis will establish a platform for reading Tawhai in regards to her literary legacy and in the context of contemporary thinking, drawing on cultural theorist Stuart Hall and his theory on identity formation and identity politics as well as indigenous writings experts Patrick Evans and Chadwick Allen. This thesis will then move into its second section, which is an analysis of some of the overarching themes that can be found in the short stories of Tawhai’s literary foremothers, Sturm, Grace and Hulme. These include, for example, racism and discrimination, loss of ancestral lands, problems to do with urbanization and family violence.

The third and final section of this thesis will then consider Tawhai’s representation of contemporary experience, taking a particular interest in her portrayals of contemporary multicultural ethnic identities as well as the flexible and provisional nature of gendered and sexual identities today. The final subsection will then analyze her representations of the new family and social structures that may have replaced the traditional family model.

Through a close reading of her short stories and an appreciation of the legacy that she bears, this thesis will show how Tawhai’s work is a larger lens of contemporary New Zealand society as well as a significant addition to the Maori literary tradition.

year: 2014