title: Variable abstraction and approximations in supervisory control synthesis

authors: Teixeira, Marcelo

subjects: computer science

abstract: This paper proposes a method to simplify Extended Finite-state Automata (EFA) in such a way the least restrictive controllable supervisor is preserved. The method is based on variable abstraction, which involves the identification and removal of irrelevant variables from a model. Variable abstraction preserves controllability, and the paper shows how approximations can be used to ascertain least restrictiveness of the synthesis result. The approach has the modelling benefits of Extended Finite-state Automata, leads to optimal control solutions, and reduces the synthesis cost. An example of a manufacturing system illustrates the contributions.

text: Variable abstraction and approximations in supervisory control synthesis This paper proposes a method to simplify Extended Finite-state Automata (EFA) in such a way the least restrictive controllable supervisor is preserved. The method is based on variable abstraction, which involves the identification and removal of irrelevant variables from a model. Variable abstraction preserves controllability, and the paper shows how approximations can be used to ascertain least restrictiveness of the synthesis result. The approach has the modelling benefits of Extended Finite-state Automata, leads to optimal control solutions, and reduces the synthesis cost. An example of a manufacturing system illustrates the contributions.

year: 2013

title: Improving Water Quality through Environmental Policies and Farm Management: an Environmental Economics Analysis of Dairy Farming in  Karapiro Catchment

authors: Ramilan, Thiagarajah

subjects: Water quality

abstract: This research explores the environmental and economic implications of nitrogen discharge abatement from dairy farms. This thesis develops a framework to analyse agri-environmental policies using bio economic modelling. A novel approach has been developed using farm survey data for catchment scale modelling and policy analysis. 

Policy analysis is facilitated by various modelling techniques and software. Geographic Information Systems (GIS) are used to convert data from multiple sources to a common platform for policy analysis. Whole dairy farm system simulations coupled with a Metamodel built on the Overseer software are used to establish the relationship between farm economic returns and nitrogen discharges. This relationship is used to derive abatement costs and resolve policy implementation challenges. Data Envelopment Analysis is used to develop Environmental economic efficiency measures. Finally a stylized model is used to determine spatially optimal riparian buffer strips. 

The results show that the differences in abatement costs and environmental efficiency between farming systems are significant. The adverse effects of information asymmetry can be effectively minimized by adopting differentiated incentives and target monitoring. Riparian buffers are a cost effective abatement tool that complement abatement at the intensive margin. Clear understanding of farm heterogeneity will help to design effective policies.

Techniques for the measurement of policy impact have been successfully developed and add significantly to our knowledge of the underlying relationships. The use of simulated data for agri-environmental policy analysis is versatile and is expected to have several valuable applications. These methods can be applied to other geographic areas and research domains. This thesis provides useful tools for policy makers seeking to develop empirically informed agri environmental policy.

text: Improving Water Quality through Environmental Policies and Farm Management: an Environmental Economics Analysis of Dairy Farming in  Karapiro Catchment This research explores the environmental and economic implications of nitrogen discharge abatement from dairy farms. This thesis develops a framework to analyse agri-environmental policies using bio economic modelling. A novel approach has been developed using farm survey data for catchment scale modelling and policy analysis. 

Policy analysis is facilitated by various modelling techniques and software. Geographic Information Systems (GIS) are used to convert data from multiple sources to a common platform for policy analysis. Whole dairy farm system simulations coupled with a Metamodel built on the Overseer software are used to establish the relationship between farm economic returns and nitrogen discharges. This relationship is used to derive abatement costs and resolve policy implementation challenges. Data Envelopment Analysis is used to develop Environmental economic efficiency measures. Finally a stylized model is used to determine spatially optimal riparian buffer strips. 

The results show that the differences in abatement costs and environmental efficiency between farming systems are significant. The adverse effects of information asymmetry can be effectively minimized by adopting differentiated incentives and target monitoring. Riparian buffers are a cost effective abatement tool that complement abatement at the intensive margin. Clear understanding of farm heterogeneity will help to design effective policies.

Techniques for the measurement of policy impact have been successfully developed and add significantly to our knowledge of the underlying relationships. The use of simulated data for agri-environmental policy analysis is versatile and is expected to have several valuable applications. These methods can be applied to other geographic areas and research domains. This thesis provides useful tools for policy makers seeking to develop empirically informed agri environmental policy.

year: 2008

title: Whakapapa Ora: An exploration of Māori Identity through Whakapapa

authors: Ngawhare, Rauna Maria

subjects: Whakapapa

abstract: This thesis set out to explore Māori identity through access to whakapapa. As whānau, hapū, and iwi, we have a responsibility to future generations to ensure access to whakapapa is inclusive. Therefore, access to whakapapa in today’s world must also consider contemporary approaches, including the use of technology to engage the next generation in learning about, and connecting with, whakapapa. 

The research is centred on the question ‘How can whakapapa be accessed safely in culturally appropriate ways that evolve with twenty-first-century systems?’ I use contemporary pūrākau to review traditional access to whakapapa, supported by a Kaupapa Māori approach to frame the research. Kaupapa Māori Theory, Ngā Takepū, and Pūrākau Methodology (underpinned by Qualitative Methodology and Thematic Analysis) give an overview of the methodologies and methods used herein. Five semi-structured interviews with whānau affiliated to Ngāti Kahungunu ki Heretaunga and Taranaki iwi were conducted. Each share their lived experiences as Māori to support an understanding of identity through whakapapa.  

The results suggest whānau Māori who access whakapapa (in its many forms), will undergo a process of decolonisation. This requires adequate support in the form of kaitiakitanga, necessary to gain a better understanding of Te Ao Māori tikanga and kawa. Whakapapa access develops this process. However, further research is required to fully appreciate ‘Whakapapa Ora’ as a foundation for safe access to whakapapa in the twenty-first century.

text: Whakapapa Ora: An exploration of Māori Identity through Whakapapa This thesis set out to explore Māori identity through access to whakapapa. As whānau, hapū, and iwi, we have a responsibility to future generations to ensure access to whakapapa is inclusive. Therefore, access to whakapapa in today’s world must also consider contemporary approaches, including the use of technology to engage the next generation in learning about, and connecting with, whakapapa. 

The research is centred on the question ‘How can whakapapa be accessed safely in culturally appropriate ways that evolve with twenty-first-century systems?’ I use contemporary pūrākau to review traditional access to whakapapa, supported by a Kaupapa Māori approach to frame the research. Kaupapa Māori Theory, Ngā Takepū, and Pūrākau Methodology (underpinned by Qualitative Methodology and Thematic Analysis) give an overview of the methodologies and methods used herein. Five semi-structured interviews with whānau affiliated to Ngāti Kahungunu ki Heretaunga and Taranaki iwi were conducted. Each share their lived experiences as Māori to support an understanding of identity through whakapapa.  

The results suggest whānau Māori who access whakapapa (in its many forms), will undergo a process of decolonisation. This requires adequate support in the form of kaitiakitanga, necessary to gain a better understanding of Te Ao Māori tikanga and kawa. Whakapapa access develops this process. However, further research is required to fully appreciate ‘Whakapapa Ora’ as a foundation for safe access to whakapapa in the twenty-first century.

year: 2019