title: An exploration of using the intel AVX2 gather load instructions for vectorised image processing

authors: Cree, Michael J.

subjects: SIMD

abstract: Processing image data with single-instruction multiple-data (SIMD) CPU instructions provides a means of vectorising, thus speeding up execution, of standard image processing operators. SIMD register loads normally load from consecutive locations in memory, that is, consecutive pixels in a row of the image. For some algorithms, however, data dependencies between pixels along rows render SIMD vectorisation useless. If one could efficiently load pixels from columns of images this problem would be fixed. The Intel AVX2 CPU extension introduces an instruction for the gather loading of data from multiple memory locations into a single CPU SIMD register. We explore using these instructions for column loads of image data in two common image operations, transposing images and mean filtering, to test 1) whether they provide useful speed-ups when other vectorised approaches exist (and find that they do not), and 2) whether they provide means of implementing operations that otherwise would be difficult or extremely inefficient to achieve without a column load (they can provide speed-ups over scalar code).

text: An exploration of using the intel AVX2 gather load instructions for vectorised image processing Processing image data with single-instruction multiple-data (SIMD) CPU instructions provides a means of vectorising, thus speeding up execution, of standard image processing operators. SIMD register loads normally load from consecutive locations in memory, that is, consecutive pixels in a row of the image. For some algorithms, however, data dependencies between pixels along rows render SIMD vectorisation useless. If one could efficiently load pixels from columns of images this problem would be fixed. The Intel AVX2 CPU extension introduces an instruction for the gather loading of data from multiple memory locations into a single CPU SIMD register. We explore using these instructions for column loads of image data in two common image operations, transposing images and mean filtering, to test 1) whether they provide useful speed-ups when other vectorised approaches exist (and find that they do not), and 2) whether they provide means of implementing operations that otherwise would be difficult or extremely inefficient to achieve without a column load (they can provide speed-ups over scalar code).

year: 2018

title: Connecting, synchronising, and dating with tephras: principles and applications of tephrochronology in Quaternary research

authors: Lowe, David J.

abstract: Tephrochronology is a unique method for linking and dating geological, palaeoecological, palaeoclimatic, or archaeological sequences or events. The method relies firstly on stratigraphy and the law of superposition, which apply in any study that connects or correlates deposits from one place to another. Secondly, it relies on characterising and hence identifying or ‘fingerprinting’ tephra layers using either physical properties evident in the field or those obtained from laboratory analysis, including mineralogical examination by optical microscopy or geochemical analysis of glass shards or crystals (e.g., Fe-Ti oxides, ferromagnesian minerals) using the electron microprobe and other tools. Thirdly, the method is enhanced when a numerical age is obtained for a tephra layer by (1) radiometric methods such as radiocarbon, fission-track, U-series, (U-Th)/He, or Ar/Ar dating, (2) incremental dating methods including dendrochronology or varved sediments or layering in ice cores, or (3) age-equivalent methods such as palaeomagnetism or correlation with marine oxygen isotope stages or palynostratigraphy. Once known, that age can be transferred from one site to the next using stratigraphic methods and by matching compositional characteristics, i.e., comparing ‘fingerprints’ from each layer. Used this way, tephrochronology is an age-equivalent dating method.

text: Connecting, synchronising, and dating with tephras: principles and applications of tephrochronology in Quaternary research Tephrochronology is a unique method for linking and dating geological, palaeoecological, palaeoclimatic, or archaeological sequences or events. The method relies firstly on stratigraphy and the law of superposition, which apply in any study that connects or correlates deposits from one place to another. Secondly, it relies on characterising and hence identifying or ‘fingerprinting’ tephra layers using either physical properties evident in the field or those obtained from laboratory analysis, including mineralogical examination by optical microscopy or geochemical analysis of glass shards or crystals (e.g., Fe-Ti oxides, ferromagnesian minerals) using the electron microprobe and other tools. Thirdly, the method is enhanced when a numerical age is obtained for a tephra layer by (1) radiometric methods such as radiocarbon, fission-track, U-series, (U-Th)/He, or Ar/Ar dating, (2) incremental dating methods including dendrochronology or varved sediments or layering in ice cores, or (3) age-equivalent methods such as palaeomagnetism or correlation with marine oxygen isotope stages or palynostratigraphy. Once known, that age can be transferred from one site to the next using stratigraphic methods and by matching compositional characteristics, i.e., comparing ‘fingerprints’ from each layer. Used this way, tephrochronology is an age-equivalent dating method.

year: 2016

title: Caught in the cross-fire: the realities of being Māori at a bicultural law school

authors: Papuni-Ball, Makere

abstract: This thesis examines the first Waikato Māori Law Graduates’ experiences at law school and our employment choices. It has been written as a result of a research project which was conducted in 1994. The paper begins with establishing the importance of other Māori the guidelines on this project. In this discussion, my role as the researcher is explained together with how the original research project impacted upon this thesis.

Waikato School of Law was established in an era of socio-political changes in our society. Te Matahauariki Report supported its establishment based upon proven demand for law graduates. It also envisaged the School as being a meeting place for all who attended, an institution which might encourage relationships between Māori and Pakeha societies. The Council of Legal Education supported the need to have at least one law school which would not reflect the traditional legal education system and acknowledged the need to incorporate a Māori perspective. Tainui as tangata whenua hoped the school would provide opportunities for Māori students, including Māori in the curriculum and assist in promoting research ensuring the recognition of Māori lore/law.

Amongst this backdrop, the most important reason why we came to law school was because of our whānau expectations. It is the accountability and responsibility we have as Māori to our whānau and the wider Māori community that is a major theme throughout this thesis. As students we were expected to utilise our skills to benefit our wider Māori networks.

We had expected that the School would provide us with a legal education which would be enriched in Māori kaupapa. Our experiences tell another story. Instead of being educated in Māori tikanga and the true discourse of the law as a tool of oppression, we were exposed to continual suppression of our cultural heritage. In class we had become the teachers of the Māori content.

The School, although admiral in its aims, was not prepared in structure, staff or mental processes for biculturalism. The consequences for the Māori students who were exposed to this structure was devastating. Our experiences of being discriminated against and made to justify our Māori perspective against the backdrop of the dominant Pakeha legal culture have affected our perceptions of the law. The myths of one law for all and the neutrality of the justice system have resulted in our choosing to work in jobs that will continue to benefit Māori.

It is suggested that our legal education has influenced our choices to work in areas which focus on benefiting the Māori community. In those monocultural work areas which have few Māori practising, this is because such places repel those of us who know that such work places perpetuate the dominant Pakeha culture. Māori struggle against the oppressive presence of the dominant culture.

This thesis calls upon my own experiences and the experiences of my fellow Māori law graduates. It is a starting point for other Māori to write about their experiences and to reassert Māori rangatiratanga not only in law school, but in the wider community.

text: Caught in the cross-fire: the realities of being Māori at a bicultural law school This thesis examines the first Waikato Māori Law Graduates’ experiences at law school and our employment choices. It has been written as a result of a research project which was conducted in 1994. The paper begins with establishing the importance of other Māori the guidelines on this project. In this discussion, my role as the researcher is explained together with how the original research project impacted upon this thesis.

Waikato School of Law was established in an era of socio-political changes in our society. Te Matahauariki Report supported its establishment based upon proven demand for law graduates. It also envisaged the School as being a meeting place for all who attended, an institution which might encourage relationships between Māori and Pakeha societies. The Council of Legal Education supported the need to have at least one law school which would not reflect the traditional legal education system and acknowledged the need to incorporate a Māori perspective. Tainui as tangata whenua hoped the school would provide opportunities for Māori students, including Māori in the curriculum and assist in promoting research ensuring the recognition of Māori lore/law.

Amongst this backdrop, the most important reason why we came to law school was because of our whānau expectations. It is the accountability and responsibility we have as Māori to our whānau and the wider Māori community that is a major theme throughout this thesis. As students we were expected to utilise our skills to benefit our wider Māori networks.

We had expected that the School would provide us with a legal education which would be enriched in Māori kaupapa. Our experiences tell another story. Instead of being educated in Māori tikanga and the true discourse of the law as a tool of oppression, we were exposed to continual suppression of our cultural heritage. In class we had become the teachers of the Māori content.

The School, although admiral in its aims, was not prepared in structure, staff or mental processes for biculturalism. The consequences for the Māori students who were exposed to this structure was devastating. Our experiences of being discriminated against and made to justify our Māori perspective against the backdrop of the dominant Pakeha legal culture have affected our perceptions of the law. The myths of one law for all and the neutrality of the justice system have resulted in our choosing to work in jobs that will continue to benefit Māori.

It is suggested that our legal education has influenced our choices to work in areas which focus on benefiting the Māori community. In those monocultural work areas which have few Māori practising, this is because such places repel those of us who know that such work places perpetuate the dominant Pakeha culture. Māori struggle against the oppressive presence of the dominant culture.

This thesis calls upon my own experiences and the experiences of my fellow Māori law graduates. It is a starting point for other Māori to write about their experiences and to reassert Māori rangatiratanga not only in law school, but in the wider community.

year: 1996