title: Prior Robustness for Bayesian Implementation of the Fault Tree Analysis

authors: Joshi, Chaitanya

subjects: Science & Technology

abstract: We propose a prior robustness approach for the Bayesian implementation of the fault tree analysis (FTA). FTA is often used to evaluate risk in large, safety critical systems but has limitations due to its static structure. Bayesian approaches have been proposed as a superior alternative to it, however, this involves prior elicitation, which is not straightforward. We show that minor misspecification of priors for elementary events can result in a significant prior misspecification for the top event. A large amount of data is required to correctly update a misspecified prior and such data may not be available for many complex, safety critical systems. In such cases, prior misspecification equals posterior misspecification. Therefore, there is a need to develop a robustness approach for FTA, which can quantify the effects of prior misspecification on the posterior analysis. Here, we propose the first prior robustness approach specifically developed for FTA. We not only prove a few important mathematical properties of this approach, but also develop easy to use Monte Carlo sampling algorithms to implement this approach on any given fault tree with and and/or or gates. We then implement this Bayesian robustness approach on two real-life examples: a spacecraft re-entry example and a feeding control system example. We also provide a step-by-step illustration of how this approach can be applied to a real-life problem.

text: Prior Robustness for Bayesian Implementation of the Fault Tree Analysis We propose a prior robustness approach for the Bayesian implementation of the fault tree analysis (FTA). FTA is often used to evaluate risk in large, safety critical systems but has limitations due to its static structure. Bayesian approaches have been proposed as a superior alternative to it, however, this involves prior elicitation, which is not straightforward. We show that minor misspecification of priors for elementary events can result in a significant prior misspecification for the top event. A large amount of data is required to correctly update a misspecified prior and such data may not be available for many complex, safety critical systems. In such cases, prior misspecification equals posterior misspecification. Therefore, there is a need to develop a robustness approach for FTA, which can quantify the effects of prior misspecification on the posterior analysis. Here, we propose the first prior robustness approach specifically developed for FTA. We not only prove a few important mathematical properties of this approach, but also develop easy to use Monte Carlo sampling algorithms to implement this approach on any given fault tree with and and/or or gates. We then implement this Bayesian robustness approach on two real-life examples: a spacecraft re-entry example and a feeding control system example. We also provide a step-by-step illustration of how this approach can be applied to a real-life problem.

year: 2018

title: Reflecting on the development of a new school subject: the development of technology education in New Zealand.

authors: Jones, Alister

subjects: curriculum planning

abstract: The last 10 years have seen the production of curricula in Australia, the United Kingdom, USA, Canada, Hong Kong and New Zealand that emphasise the importance of students developing technological literacy. This paper traces the development of a new subject - technology education - in the New Zealand curriculum and explores the politics of development of a new subject as well as the theoretical stances and research that contributed to its development from 1992 until 2005. This paper outlines the various stages of development including curriculum development, teacher development, and the move to creating a classroom research agenda to enhance the teaching and learning in technology education. The paper reinforces the notion that significant gains can be made in curriculum, teaching, learning and assessment when research and development are conducted in an ongoing manner.

text: Reflecting on the development of a new school subject: the development of technology education in New Zealand. The last 10 years have seen the production of curricula in Australia, the United Kingdom, USA, Canada, Hong Kong and New Zealand that emphasise the importance of students developing technological literacy. This paper traces the development of a new subject - technology education - in the New Zealand curriculum and explores the politics of development of a new subject as well as the theoretical stances and research that contributed to its development from 1992 until 2005. This paper outlines the various stages of development including curriculum development, teacher development, and the move to creating a classroom research agenda to enhance the teaching and learning in technology education. The paper reinforces the notion that significant gains can be made in curriculum, teaching, learning and assessment when research and development are conducted in an ongoing manner.

year: 2007

title: The contested shift to a bicultural understanding of place heritage in Aotearoa New Zealand

authors: Passey, Emma

abstract: This article explores contemporary threads in the heritage history of Aotearoa New Zealand, as we witness in real-time the emergence of alternative narratives of Indigenous heritage, in contrast to those of Western dominated modernity and colonial hegemony. Moves to actively decolonise heritage studies is creating shifts in the bicultural understanding of culture and heritage to overtly include place heritage. As this new framing emerges, wider acknowledgement of the significance of Māori heritage landscapes is growing. This is explored here in a series of four case-studies. Each account illustrates how Indigenous Māori voices have gained momentum, and reinforces how Aotearoa New Zealand is transitioning to greater bicultural appreciation through inclusion, changes in social and cultural conventions, and new interpretations of dominant narratives using tools like critical heritage studies and existing legal conventions. This evolution of heritage values is not without repeated contestation, however. Positively, increasing numbers of settler-Pākehā (non-Māori) as well as those colonised, no longer believe or accept the histories previously told. Much needed, robust, and sometimes difficult discussions are taking place, enabling New Zealanders to reconsider the significance of what heritage means to all its people.

text: The contested shift to a bicultural understanding of place heritage in Aotearoa New Zealand This article explores contemporary threads in the heritage history of Aotearoa New Zealand, as we witness in real-time the emergence of alternative narratives of Indigenous heritage, in contrast to those of Western dominated modernity and colonial hegemony. Moves to actively decolonise heritage studies is creating shifts in the bicultural understanding of culture and heritage to overtly include place heritage. As this new framing emerges, wider acknowledgement of the significance of Māori heritage landscapes is growing. This is explored here in a series of four case-studies. Each account illustrates how Indigenous Māori voices have gained momentum, and reinforces how Aotearoa New Zealand is transitioning to greater bicultural appreciation through inclusion, changes in social and cultural conventions, and new interpretations of dominant narratives using tools like critical heritage studies and existing legal conventions. This evolution of heritage values is not without repeated contestation, however. Positively, increasing numbers of settler-Pākehā (non-Māori) as well as those colonised, no longer believe or accept the histories previously told. Much needed, robust, and sometimes difficult discussions are taking place, enabling New Zealanders to reconsider the significance of what heritage means to all its people.

year: 2023-01-01