title: Cause of pulse artefacts inherent to the electrodes of neuromodulation implants

authors: Single, Peter

abstract: The current pulses delivered through platinum electrodes by medical implants to recruit neurones give rise to slowly-decaying voltage tails, called "artefacts''. These tails make measurement of evoked potentials following the pulses very difficult. We present evidence to show that in a typical clinical scenario these tails are mostly caused by concentration gradients of species induced in the electrical double layer adsorbed onto the surface of both stimulating and passive electrodes. A compact model is presented that allows simulation of these artefacts. The model is verified against measurements made in saline. This shows that electrode artefacts are an intrinsic property of the conductive electrodes of a lead.

text: Cause of pulse artefacts inherent to the electrodes of neuromodulation implants The current pulses delivered through platinum electrodes by medical implants to recruit neurones give rise to slowly-decaying voltage tails, called "artefacts''. These tails make measurement of evoked potentials following the pulses very difficult. We present evidence to show that in a typical clinical scenario these tails are mostly caused by concentration gradients of species induced in the electrical double layer adsorbed onto the surface of both stimulating and passive electrodes. A compact model is presented that allows simulation of these artefacts. The model is verified against measurements made in saline. This shows that electrode artefacts are an intrinsic property of the conductive electrodes of a lead.

year: 2018

title: Bound analysis for Whiley programs

authors: Weng, Min-Hsien

subjects: Static Analysis

abstract: The Whiley compiler can generate naive C code, but the code is inefficient because it uses infinite integers and dynamic array sizes. Our project goal is to build up a compiler that can translate Whiley programs into efficient OpenCL code with fixed-size integer types and fixed-size arrays, for parallel execution on GPUs. This paper presents an abstract interpretation-based bound inference approach along with symbolic analysis for Whiley programs. The source Whiley program is first analyzed by using our symbolic analyzer to find the matching pattern and make any necessary program transformation. Then the bound analyzer is used to analyze the transformed program to make use of primitive integer types rather than third-party infinite integer type (e.g. using GMP arbitrary precision library). The bound analysis results provide conservative estimates of the ranges of integer variables and array sizes so that efficient code can be generated and integer overflows avoided. The bound analyzer combines the bound consistency technique along with a widening operator to give fast time of solving program constraints and of converging to the fixed point. Several example programs are used to illustrate the bound analyzer algorithm and the program transformation.

text: Bound analysis for Whiley programs The Whiley compiler can generate naive C code, but the code is inefficient because it uses infinite integers and dynamic array sizes. Our project goal is to build up a compiler that can translate Whiley programs into efficient OpenCL code with fixed-size integer types and fixed-size arrays, for parallel execution on GPUs. This paper presents an abstract interpretation-based bound inference approach along with symbolic analysis for Whiley programs. The source Whiley program is first analyzed by using our symbolic analyzer to find the matching pattern and make any necessary program transformation. Then the bound analyzer is used to analyze the transformed program to make use of primitive integer types rather than third-party infinite integer type (e.g. using GMP arbitrary precision library). The bound analysis results provide conservative estimates of the ranges of integer variables and array sizes so that efficient code can be generated and integer overflows avoided. The bound analyzer combines the bound consistency technique along with a widening operator to give fast time of solving program constraints and of converging to the fixed point. Several example programs are used to illustrate the bound analyzer algorithm and the program transformation.

year: 2015

title: Tangi and State Funeral: Te Arikinui Dame Te Atairangikaahu and Prime Minister Norman Kirk

authors: McRae, Karyn Okeroa

subjects: Tangi

abstract: The tangi of Te Arikinui Dame Te Atairangikaahu (Te Arikinui) in 2006 paralleled the State funerals for New Zealand Prime Ministers like Norman Kirk who died in 1974. State funerals require the huge mobilization of people and resources and always attract the attention of the national and international media. The death of a Prime Minister is news worthy, but what of a minority indigenous fourth world leader like Te Arikinui? Why did her passing attract so much media attention? In this study I argue that media representation of the tangi of Te Arikinui was largely about social, cultural and symbolic capital. In media saturated societies such as Aotearoa/New Zealand, through mainstream media outlets like TV One News and the Waikato Times, Te Arikinui’s tangi event claimed a dominant space in the lives of Maori and non Maori alike. The data source includes print news media coverage of the tangi of Te Arikinui and the State funeral of Norman Kirk. Descriptive narrative and abductive analysis inform the methodology used in this study. As expected, print media reporting of both events progressed through the three stages identified by Durkheim, those of, separation, liminality and reincorporation. The ownership of death, the deceased and the continued possession of their mortal remains, itself a cultural object with symbolic and cultural capital, reflected the actual power and control of the possessor. State funerals and tangi are about the ritualized performance of grief and mourning, and require the appropriate social, cultural and symbolic capital for its enactment.

text: Tangi and State Funeral: Te Arikinui Dame Te Atairangikaahu and Prime Minister Norman Kirk The tangi of Te Arikinui Dame Te Atairangikaahu (Te Arikinui) in 2006 paralleled the State funerals for New Zealand Prime Ministers like Norman Kirk who died in 1974. State funerals require the huge mobilization of people and resources and always attract the attention of the national and international media. The death of a Prime Minister is news worthy, but what of a minority indigenous fourth world leader like Te Arikinui? Why did her passing attract so much media attention? In this study I argue that media representation of the tangi of Te Arikinui was largely about social, cultural and symbolic capital. In media saturated societies such as Aotearoa/New Zealand, through mainstream media outlets like TV One News and the Waikato Times, Te Arikinui’s tangi event claimed a dominant space in the lives of Maori and non Maori alike. The data source includes print news media coverage of the tangi of Te Arikinui and the State funeral of Norman Kirk. Descriptive narrative and abductive analysis inform the methodology used in this study. As expected, print media reporting of both events progressed through the three stages identified by Durkheim, those of, separation, liminality and reincorporation. The ownership of death, the deceased and the continued possession of their mortal remains, itself a cultural object with symbolic and cultural capital, reflected the actual power and control of the possessor. State funerals and tangi are about the ritualized performance of grief and mourning, and require the appropriate social, cultural and symbolic capital for its enactment.

year: 2010