title: A novel machine learning model to predict the moment capacity of cold-formed steel channel beams with edge-stiffened and un-stiffened web holes

authors: Dai, Yecheng

subjects: cold-formed steel

abstract: A novel machine learning model, eXtreme Gradient Boosting (XGBoost), was used for the purpose of evaluating the moment capacity of cold-formed steel (CFS) channel beams with edge-stiffened web holes subject to bending. A total of 1620 data points were generated for training the XGBoost model, using an elasto-plastic finite element model which was validated against 12 sets of test data taken from the existing literature. The R2 score of XGBoost predictions for the moment capacity was around 99%. The performance of current design equations was evaluated through the comparison of their results against those obtained from the XGBoost model. The moment capacities obtained from the XGBoost testing dataset were also compared with that determined from the existing design equations for un-stiffened holes (USH) and edge-stiffened holes (ESH). The moment capacities determined from the current design equations for USH and ESH were found to be excessively conservative by 38.3%, and unconservative by 36.2% on average, respectively. Therefore, new design equations were proposed based on the results of parametric study using the XGBoost model. In the detailed parametric analysis, the effects of web depth, section thickness, and beam length on the moment capacity of channel beams (CFSCB) with ESH were considered. From the results of XGBoost outputs, the absolute percentage error of new design equations for that based on the strengths of unperforated CFSCB was 8.78%, and for that based on the strengths of CFSCB with USH, the absolute percentage error was 13.7%. Additionally, a reliability analysis was performed to evaluate the accuracy of the proposed equations that were used to predict the moment capacity of CFS channel beams with ESH subject to bending. The reliability indices of all the proposed equations were greater than 2.5 which can be reliable as per the guidelines of AISI.

text: A novel machine learning model to predict the moment capacity of cold-formed steel channel beams with edge-stiffened and un-stiffened web holes A novel machine learning model, eXtreme Gradient Boosting (XGBoost), was used for the purpose of evaluating the moment capacity of cold-formed steel (CFS) channel beams with edge-stiffened web holes subject to bending. A total of 1620 data points were generated for training the XGBoost model, using an elasto-plastic finite element model which was validated against 12 sets of test data taken from the existing literature. The R2 score of XGBoost predictions for the moment capacity was around 99%. The performance of current design equations was evaluated through the comparison of their results against those obtained from the XGBoost model. The moment capacities obtained from the XGBoost testing dataset were also compared with that determined from the existing design equations for un-stiffened holes (USH) and edge-stiffened holes (ESH). The moment capacities determined from the current design equations for USH and ESH were found to be excessively conservative by 38.3%, and unconservative by 36.2% on average, respectively. Therefore, new design equations were proposed based on the results of parametric study using the XGBoost model. In the detailed parametric analysis, the effects of web depth, section thickness, and beam length on the moment capacity of channel beams (CFSCB) with ESH were considered. From the results of XGBoost outputs, the absolute percentage error of new design equations for that based on the strengths of unperforated CFSCB was 8.78%, and for that based on the strengths of CFSCB with USH, the absolute percentage error was 13.7%. Additionally, a reliability analysis was performed to evaluate the accuracy of the proposed equations that were used to predict the moment capacity of CFS channel beams with ESH subject to bending. The reliability indices of all the proposed equations were greater than 2.5 which can be reliable as per the guidelines of AISI.

year: 2022

title: The end of national standards: An opportunity to find creativity in primary mathematics?

authors: Bailey, Judy

abstract: On December 12, 2017 the Ministry of Education enacted the new Government’s commitment to end the use of National Standards writing, “schools and kura are no longer required to use and report on National Standards and Ngā Whanaketanga Rumaki Māori for the 2018 school year and beyond” (Ministry of Education, 2018).

text: The end of national standards: An opportunity to find creativity in primary mathematics? On December 12, 2017 the Ministry of Education enacted the new Government’s commitment to end the use of National Standards writing, “schools and kura are no longer required to use and report on National Standards and Ngā Whanaketanga Rumaki Māori for the 2018 school year and beyond” (Ministry of Education, 2018).

year: 2018

title: Hauora and physical education in New Zealand: perspectives of Māori and Pasifika

authors: Fitzpatrick, Katie

subjects: physical education

abstract: Discussion surrounding the concept of Hauora (Durie, 1994) in the document Health and Physical Education in the New Zealand Curriculum (Ministry of Education, 1999) has been controversial. Some writers have praised or justified its inclusion (Culpan, 1996/1997; Tasker, 1996/1997; Tinning, MacDonald, Wright & Hickey, 2001), while others accuse the writers of tokenism and misappropriation of indigenous knowledge (Hokowhitu, 2004; Salter, 2000). While existing at a political level, these debates have generally ignored student responses to and interactions with Hauora. Thus, this article intervenes in the existing debate and makes the case for the inclusion of student perspectives. My claims are made on the basis of a study into the perspectives of Māori and Pasifika students of physical education in New Zealand. The experiences of these students are related to the theory of hybridity (Besley, 2002; Bhabha, 1994), which suggests that young people actively negotiate and make critical decisions about what they think is relevant to them. I argue that the debate surrounding the concept of Hauora needs to include students' perspectives and consideration of the agency of young people in interactions with curriculum concepts.

text: Hauora and physical education in New Zealand: perspectives of Māori and Pasifika Discussion surrounding the concept of Hauora (Durie, 1994) in the document Health and Physical Education in the New Zealand Curriculum (Ministry of Education, 1999) has been controversial. Some writers have praised or justified its inclusion (Culpan, 1996/1997; Tasker, 1996/1997; Tinning, MacDonald, Wright & Hickey, 2001), while others accuse the writers of tokenism and misappropriation of indigenous knowledge (Hokowhitu, 2004; Salter, 2000). While existing at a political level, these debates have generally ignored student responses to and interactions with Hauora. Thus, this article intervenes in the existing debate and makes the case for the inclusion of student perspectives. My claims are made on the basis of a study into the perspectives of Māori and Pasifika students of physical education in New Zealand. The experiences of these students are related to the theory of hybridity (Besley, 2002; Bhabha, 1994), which suggests that young people actively negotiate and make critical decisions about what they think is relevant to them. I argue that the debate surrounding the concept of Hauora needs to include students' perspectives and consideration of the agency of young people in interactions with curriculum concepts.

year: 2005