title: Logistic model trees

authors: Landwehr, Niels

subjects: Science & Technology

abstract: Tree induction methods and linear models are popular techniques for supervised learning tasks, both for the prediction of nominal classes and continuous numeric values. For predicting numeric quantities, there has been work on combining these two schemes into ‘model trees’, i.e. trees that contain linear regression functions at the leaves. In this paper, we present an algorithm that adapts this idea for classification problems, using logistic regression instead of linear regression. We use a stagewise fitting process to construct the logistic regression models that can select relevant attributes in the data in a natural way, and show how this approach can be used to build the logistic regression models at the leaves by incrementally refining those constructed at higher levels in the tree. We compare the performance of our algorithm against that of decision trees and logistic regression on 32 benchmark UCI datasets, and show that it achieves a higher classification accuracy on average than the other two methods.

text: Logistic model trees Tree induction methods and linear models are popular techniques for supervised learning tasks, both for the prediction of nominal classes and continuous numeric values. For predicting numeric quantities, there has been work on combining these two schemes into ‘model trees’, i.e. trees that contain linear regression functions at the leaves. In this paper, we present an algorithm that adapts this idea for classification problems, using logistic regression instead of linear regression. We use a stagewise fitting process to construct the logistic regression models that can select relevant attributes in the data in a natural way, and show how this approach can be used to build the logistic regression models at the leaves by incrementally refining those constructed at higher levels in the tree. We compare the performance of our algorithm against that of decision trees and logistic regression on 32 benchmark UCI datasets, and show that it achieves a higher classification accuracy on average than the other two methods.

year: 2003-01-01

title: Rapid holistic assessment and rating of post-earthquake hospital functionality

authors: Boston, Megan

abstract: Hospitals play a critical role in ensuring community safety. It is imperative that they remain operational during and after an earthquake, to provide immediate and ongoing medical care. However, experience shows frequent closures and evacuations of hospitals during and after earthquakes. These decisions are frequently made quickly out of concern for patient and staff safety, and occur within minutes or hours of the event, prior to any formal assessment of structural and nonstructural components. Emergency managers and facility operators need a rapid rating tool to assess damage and predict hospital functionality based on limited information. Such a tool would improve access to medical services and reduce the number of unnecessary hospital evacuations and closures during a critical time of earthquake recovery. This research project works on creating the framework for developing a modelling tool that estimates functionality based on estimated physical damage and other disruptions at the time of an earthquake and predicts the ability of the hospital to provide medical care to the injured. The model incorporates a holistic evaluation matrix that takes inputs of physical damage, utility and back up outages, supplies and equipment, staffing, business and record functions, and facility access to estimate hospital functionality (service availability and capacity). The matrix and model aim to address challenges in estimating quantity and quality of service after a disaster. Outputs of the final model will provide a hospital rating – an indication of the hospital safety and functionality – and inform decisions for evacuations, partial or complete closure, or continued operations.

text: Rapid holistic assessment and rating of post-earthquake hospital functionality Hospitals play a critical role in ensuring community safety. It is imperative that they remain operational during and after an earthquake, to provide immediate and ongoing medical care. However, experience shows frequent closures and evacuations of hospitals during and after earthquakes. These decisions are frequently made quickly out of concern for patient and staff safety, and occur within minutes or hours of the event, prior to any formal assessment of structural and nonstructural components. Emergency managers and facility operators need a rapid rating tool to assess damage and predict hospital functionality based on limited information. Such a tool would improve access to medical services and reduce the number of unnecessary hospital evacuations and closures during a critical time of earthquake recovery. This research project works on creating the framework for developing a modelling tool that estimates functionality based on estimated physical damage and other disruptions at the time of an earthquake and predicts the ability of the hospital to provide medical care to the injured. The model incorporates a holistic evaluation matrix that takes inputs of physical damage, utility and back up outages, supplies and equipment, staffing, business and record functions, and facility access to estimate hospital functionality (service availability and capacity). The matrix and model aim to address challenges in estimating quantity and quality of service after a disaster. Outputs of the final model will provide a hospital rating – an indication of the hospital safety and functionality – and inform decisions for evacuations, partial or complete closure, or continued operations.

year: 2019

title: An outsider's guide to public oral history in New Zealand

authors: Mahuika, Nepia

subjects: Oral history

abstract: At the beginning of this century, public history in New Zealand was considered a ‘new term’ in historical practice, described as crucial in both ‘the emergence of professional history writing’ and the assertion of ‘cultural nationalism.’¹ In the past decade, scholars here have highlighted its breadth and significance in ‘the employment of historians and the historical method outside academia; in government, private companies, the media, historical societies and museums, as well as those working in private practice.’² Oral history has also become a significant part of public history’s nation-making, key in the collecting of exceptional and ‘ordinary’ public voices.³ For Māori, current definitions of oral and public history are problematic because, as this essay suggests, both are constructed within Pākehā-centric perspectives of history, tradition, orality and what counts as ‘public.’ Public history has been called a ‘slippery process’, often shaped in a contrast between ‘people’s history’ and a ‘search for social cohesion’.4 This search for ‘cohesion’ is a familiar colonial refrain that fuels a healthy native scepticism of public history as yet another settler-centric invention that keeps us on the outside. This essay considers the ways in which public oral history in New Zealand is articulated, noting how this is done within narrow definitions and binaries that displace, ignore, or distort, indigenous perspectives. It suggests a rethinking of oral history as a movement beyond current binaries in the field, and advocates a widening of the meaning of oral sources, methods and politics, in order to include indigenous definitions as legitimately oral and public. This analysis is decolonial, not because it seeks an eradication of nationalism, but because it seeks to disrupt colonial-centric meanings of oral and public history by recentering Māori perspectives as legitimate to the New Zealand public oral history vernacular.

text: An outsider's guide to public oral history in New Zealand At the beginning of this century, public history in New Zealand was considered a ‘new term’ in historical practice, described as crucial in both ‘the emergence of professional history writing’ and the assertion of ‘cultural nationalism.’¹ In the past decade, scholars here have highlighted its breadth and significance in ‘the employment of historians and the historical method outside academia; in government, private companies, the media, historical societies and museums, as well as those working in private practice.’² Oral history has also become a significant part of public history’s nation-making, key in the collecting of exceptional and ‘ordinary’ public voices.³ For Māori, current definitions of oral and public history are problematic because, as this essay suggests, both are constructed within Pākehā-centric perspectives of history, tradition, orality and what counts as ‘public.’ Public history has been called a ‘slippery process’, often shaped in a contrast between ‘people’s history’ and a ‘search for social cohesion’.4 This search for ‘cohesion’ is a familiar colonial refrain that fuels a healthy native scepticism of public history as yet another settler-centric invention that keeps us on the outside. This essay considers the ways in which public oral history in New Zealand is articulated, noting how this is done within narrow definitions and binaries that displace, ignore, or distort, indigenous perspectives. It suggests a rethinking of oral history as a movement beyond current binaries in the field, and advocates a widening of the meaning of oral sources, methods and politics, in order to include indigenous definitions as legitimately oral and public. This analysis is decolonial, not because it seeks an eradication of nationalism, but because it seeks to disrupt colonial-centric meanings of oral and public history by recentering Māori perspectives as legitimate to the New Zealand public oral history vernacular.

year: 2017