title: Correlation-based feature selection of discrete and numeric class machine learning

authors: Hall, Mark A.

subjects: computer science

abstract: Algorithms for feature selection fall into two broad categories: wrappers that use the learning algorithm itself to evaluate the usefulness of features and filters that evaluate features according to heuristics based on general characteristics of the data. For application to large databases, filters have proven to be more practical than wrappers because they are much faster. However, most existing filter algorithms only work with discrete classification problems. This paper describes a fast, correlation-based filter algorithm that can be applied to continuous and discrete problems. The algorithm often out-performs the well-known ReliefF attribute estimator when used as a preprocessing step for naive Bayes, instance-based learning, decision trees, locally weighted regression, and model trees. It performs more feature selection than ReliefF does-reducing the data dimensionality by fifty percent in most cases. Also, decision and model trees built from the preprocessed data are often significantly smaller.

text: Correlation-based feature selection of discrete and numeric class machine learning Algorithms for feature selection fall into two broad categories: wrappers that use the learning algorithm itself to evaluate the usefulness of features and filters that evaluate features according to heuristics based on general characteristics of the data. For application to large databases, filters have proven to be more practical than wrappers because they are much faster. However, most existing filter algorithms only work with discrete classification problems. This paper describes a fast, correlation-based filter algorithm that can be applied to continuous and discrete problems. The algorithm often out-performs the well-known ReliefF attribute estimator when used as a preprocessing step for naive Bayes, instance-based learning, decision trees, locally weighted regression, and model trees. It performs more feature selection than ReliefF does-reducing the data dimensionality by fifty percent in most cases. Also, decision and model trees built from the preprocessed data are often significantly smaller.

year: 2000-05

title: Restraints of change : limits to 'managed retreats' in Aotearoa New Zealand

authors: Hanna, Christina Jane

subjects: managed retreat

abstract: Managed retreat is an important strategy for natural hazard risk reduction and climate change adaptation, but its operationalisation brings many challenges, even when it is compelling. With significant built, cultural and infrastructural assets sited on low lying coastal land, and settlements traversing fault lines, flood plains, volcanic fields, and debris flow fans, remedying unsustainable land use patterns is essential to building societal resilience. To progress managed retreat from rhetoric to reality, however, New Zealand’s governance framework must be fit for purpose.
The decision-making challenge for managed retreat in New Zealand rests predominantly with environmental planning and the mandated promotion of sustainable management of natural and physical resources. The focus of this research is to examine the role of environmental planning in enabling managed retreat in New Zealand, identify and analyse the potential mechanisms available, and consider opportunities to improve practice. Quantitative and qualitative methods are applied to investigate the function and effect of the various instruments able to influence the practice of managed retreat, identify significant barriers and enablers, ascertain public perceptions towards policy, and consider governance constraints and the prospects to build institutional capacity. 
The research finds that the term ‘managed retreat’ incorporates a broad array of regulatory and financial mechanisms, with the potential to reduce exposure to a range of natural hazards and disruptive environmental changes across space and time. Although the current institutional framework has elements that can address future managed retreat of new development, instruments and support for managing legacy land uses are weak. Policy learning is occurring nationwide, but fragmentation and a lack of strong and consistent direction hinders effective management of risk. Important contributions of the research include a detailed interrogation of managed retreat in policy, analysis of the significant constraints hindering its application and acceptance in New Zealand, and the development of new opportunities to pursue managed retreat in a more effective, equitable, responsive, and robust manner. A governance framework provides a foundation to better examine and consider the various types of ‘managed retreats’ which align to the nature of the problem. It also helps shed light on the areas where research, law, and policy is currently lacking, in order to continue to answer the difficult questions of managed retreat by whom, how, when, and who pays?
Overall, this research exposes the complexities inherent in a diverse array of managed retreats, which at present are constrained by a range of socio-political-cultural, economic, and institutional barriers, requiring new arrangements of the law, planning, and funding mechanisms, and potentially, alternative governance modes. Retreat is inevitable in certain local and global environs—how it is delivered will determine the success of its outcomes and ultimately, the resilience of current and future generations. Bridging the gap between managed retreat theory and practice to increase resilience is essential.

text: Restraints of change : limits to 'managed retreats' in Aotearoa New Zealand Managed retreat is an important strategy for natural hazard risk reduction and climate change adaptation, but its operationalisation brings many challenges, even when it is compelling. With significant built, cultural and infrastructural assets sited on low lying coastal land, and settlements traversing fault lines, flood plains, volcanic fields, and debris flow fans, remedying unsustainable land use patterns is essential to building societal resilience. To progress managed retreat from rhetoric to reality, however, New Zealand’s governance framework must be fit for purpose.
The decision-making challenge for managed retreat in New Zealand rests predominantly with environmental planning and the mandated promotion of sustainable management of natural and physical resources. The focus of this research is to examine the role of environmental planning in enabling managed retreat in New Zealand, identify and analyse the potential mechanisms available, and consider opportunities to improve practice. Quantitative and qualitative methods are applied to investigate the function and effect of the various instruments able to influence the practice of managed retreat, identify significant barriers and enablers, ascertain public perceptions towards policy, and consider governance constraints and the prospects to build institutional capacity. 
The research finds that the term ‘managed retreat’ incorporates a broad array of regulatory and financial mechanisms, with the potential to reduce exposure to a range of natural hazards and disruptive environmental changes across space and time. Although the current institutional framework has elements that can address future managed retreat of new development, instruments and support for managing legacy land uses are weak. Policy learning is occurring nationwide, but fragmentation and a lack of strong and consistent direction hinders effective management of risk. Important contributions of the research include a detailed interrogation of managed retreat in policy, analysis of the significant constraints hindering its application and acceptance in New Zealand, and the development of new opportunities to pursue managed retreat in a more effective, equitable, responsive, and robust manner. A governance framework provides a foundation to better examine and consider the various types of ‘managed retreats’ which align to the nature of the problem. It also helps shed light on the areas where research, law, and policy is currently lacking, in order to continue to answer the difficult questions of managed retreat by whom, how, when, and who pays?
Overall, this research exposes the complexities inherent in a diverse array of managed retreats, which at present are constrained by a range of socio-political-cultural, economic, and institutional barriers, requiring new arrangements of the law, planning, and funding mechanisms, and potentially, alternative governance modes. Retreat is inevitable in certain local and global environs—how it is delivered will determine the success of its outcomes and ultimately, the resilience of current and future generations. Bridging the gap between managed retreat theory and practice to increase resilience is essential.

year: 2019

title: Empirical analysis of Pacific, Māori and ethnic pay gaps in New Zealand

authors: Cochrane, William

abstract: A descriptive profile of the four ethnic groups, by gender, is provided to illustrate the heterogeneities across populations in terms of a number of variables grouped into the following categories: individual characteristics, educational attainment, region, household and job-related characteristics. The main empirical analysis involves estimation of the statistical contribution of observed factors (within each of the aforementioned categories) towards explaining the ethnic pay gaps. As this research is primarily aimed as an input towards the Pacific Pay Gap Inquiry being conducted by the Human Rights Commission, we focus our summary of the key findings on the Pacific – European pay gap.
This includes variables on permanent contract status, an indicator if in part-time work, occupation, and industry. These results are therefore likely an indication of the strong role of occupational segregation in the labour market. An additional factor that had a relatively strong contribution to the pay gap, particularly for the Pacific – European female gap, was educational attainment. Overall, even after accounting for differences in job-related characteristics and educational attainment, amongst a number of other observed factors, it was still found that only 27 percent of the pay gap for Pacific males (relative to Europeans) could be explained; and the corresponding proportion for females was 39 percent. The remaining portion of the Pacific Pay Gap is likely to reflect a range of causes that cannot be quantified or disentangled in this analysis – such as not including other factors of importance as they weren’t observed in the data (for example, literacy proficiency or field of study for qualification attained); ethnic differences in preferences for non-wage components of the job; unconscious bias; and discrimination.

text: Empirical analysis of Pacific, Māori and ethnic pay gaps in New Zealand A descriptive profile of the four ethnic groups, by gender, is provided to illustrate the heterogeneities across populations in terms of a number of variables grouped into the following categories: individual characteristics, educational attainment, region, household and job-related characteristics. The main empirical analysis involves estimation of the statistical contribution of observed factors (within each of the aforementioned categories) towards explaining the ethnic pay gaps. As this research is primarily aimed as an input towards the Pacific Pay Gap Inquiry being conducted by the Human Rights Commission, we focus our summary of the key findings on the Pacific – European pay gap.
This includes variables on permanent contract status, an indicator if in part-time work, occupation, and industry. These results are therefore likely an indication of the strong role of occupational segregation in the labour market. An additional factor that had a relatively strong contribution to the pay gap, particularly for the Pacific – European female gap, was educational attainment. Overall, even after accounting for differences in job-related characteristics and educational attainment, amongst a number of other observed factors, it was still found that only 27 percent of the pay gap for Pacific males (relative to Europeans) could be explained; and the corresponding proportion for females was 39 percent. The remaining portion of the Pacific Pay Gap is likely to reflect a range of causes that cannot be quantified or disentangled in this analysis – such as not including other factors of importance as they weren’t observed in the data (for example, literacy proficiency or field of study for qualification attained); ethnic differences in preferences for non-wage components of the job; unconscious bias; and discrimination.

year: 2022-07