title: Aesthetic local search of wind farm layouts

authors: Mayo, Michael

subjects: wind farm layout optimisation

abstract: The visual impact of wind farm layouts has seen little consideration in the literature on the wind farm layout optimisation problem to date. Most existing algorithms focus on optimising layouts for power or the cost of energy alone. In this paper, we consider the geometry of wind farm layouts and whether it is possible to bi-optimise a layout for both energy efficiency and the degree of visual impact that the layout exhibits. We develop a novel optimisation approach for solving the problem which measures mathematically the degree of visual impact of a layout. The approach draws inspiration from the field of architecture. To evaluate our ideas, we demonstrate them on three benchmark problems for the wind farm layout optimisation problem in conjunction with two recently-published stochastic local search algorithms. Optimal patterned layouts are shown to be very close in terms of energy efficiency to optimal non-patterned layouts.

text: Aesthetic local search of wind farm layouts The visual impact of wind farm layouts has seen little consideration in the literature on the wind farm layout optimisation problem to date. Most existing algorithms focus on optimising layouts for power or the cost of energy alone. In this paper, we consider the geometry of wind farm layouts and whether it is possible to bi-optimise a layout for both energy efficiency and the degree of visual impact that the layout exhibits. We develop a novel optimisation approach for solving the problem which measures mathematically the degree of visual impact of a layout. The approach draws inspiration from the field of architecture. To evaluate our ideas, we demonstrate them on three benchmark problems for the wind farm layout optimisation problem in conjunction with two recently-published stochastic local search algorithms. Optimal patterned layouts are shown to be very close in terms of energy efficiency to optimal non-patterned layouts.

year: 2017

title: Fast magnetic reconnection and the coalescence instability

authors: Craig, Ian J.D.

subjects: mathematics

abstract: The magnetic reconnection that occurs during the nonlinear development of the coalescence instability is considered. The structure of the reconnection region at the time of maximum current as a function of the resistivity η is analyzed in detail using a compressible magnetohydrodynamic fluid code. It is shown that the numerical results concur remarkably well with a simple scaling analysis which predicts the dependence of the reconnection region structure on η. It is argued that the flow topology is crucial in maintaining the ``fast'' reconnection rate. The results indicate a flux pileup solution in which the flux annihilation rate is approximately independent of η, whereas the Ohmic dissipation rate scales as η −1/3. The possibility that these scalings break down at lower values of η is discussed.

text: Fast magnetic reconnection and the coalescence instability The magnetic reconnection that occurs during the nonlinear development of the coalescence instability is considered. The structure of the reconnection region at the time of maximum current as a function of the resistivity η is analyzed in detail using a compressible magnetohydrodynamic fluid code. It is shown that the numerical results concur remarkably well with a simple scaling analysis which predicts the dependence of the reconnection region structure on η. It is argued that the flow topology is crucial in maintaining the ``fast'' reconnection rate. The results indicate a flux pileup solution in which the flux annihilation rate is approximately independent of η, whereas the Ohmic dissipation rate scales as η −1/3. The possibility that these scalings break down at lower values of η is discussed.

year: 1993-03

title: Kei hea te tangi a te Tūī? An exploration of Kaitiakitanga in urban spaces

authors: Walker, Erana

subjects: Kaitiakitanga

abstract: Indigenous people’s connection to the natural world differs from place to place. In Aotearoa, New Zealand, Māori connection to nature is often articulated through the concept of kaitiakitanga whilst intertwining concepts of whakapapa, wairua, mana, mauri and place. Kaitiakitanga captures the relationships, narratives and practices that Māori utilise to protect kin of the natural environment as well as Māori communities in general. Over recent decades increase use of kaitiakitanga with respect to resource management has been linked to ideas of guardianship and stewardship, departing from important aspects such as place, whakapapa, intergenerational knowledge, spirituality and resource use. Calls to recognise the diverse ways kaitiakitanga has and can be expressed by Māori have echoed through academic literature, encouraging wider perspectives and application of the concept to develop. This has reinvigorated not only the need for natures protection but also the recognition of cultural knowledges and concepts in practicing kaitiakitanga. 
 
As with most indigenous people, Māori have experienced urbanisation that has spanned across generations of whānau and hapū. Urbanisation has the ability to challenge health outcomes, cultural practices and cultural knowledge, and more importantly, relationships to nature. Growing urbanisation and environmental degradation continue to challenge people and our relationships to nature. There is now a need to understand how urban spaces may also challenge the concepts that encourage connections to nature like kaitiakitanga. Moreover, there is a need to understand if such cultural concepts can become challenged when transient Māori reside in another tribal group’s boundaries. This research provides a deeper analysis of kaitiakitanga by understanding its application within the urban space of Kirikiriroa/Hamilton. From data gathered through a survey, focus groups and interviews, this research project illustrates the experiences of Māori in the urban space who know and practice kaitiakitanga in Kirikiriroa/Hamilton. More importantly, this study posits the integral role of place connection and mana in supporting and shaping kaitiakitanga practices in urban spaces.

The data from participants shows a clear narrative of kaitiakitanga from both local and transient Māori exist and indicates that kaitiakitanga is practiced in accordance with their location and whakapapa to their area of residence. The study has found that kaitiakitanga practices have adapted to suit urban spaces allowing for both transient and local knowledges to exist within the urban space. The key findings of this research show many influences that impact kaitiakitanga practices like the recognition of childhood spaces and experiences, ideas of kinship, cultural knowledges, spirituality, mobility, nature as well as modernisation. Through exploring participants use and knowledge of kaitiakitanga, this research provides a new lens in which to view this concept and bring to the fore, the various experiences and ways that participants connect to place, people, culture and most importantly, nature.

text: Kei hea te tangi a te Tūī? An exploration of Kaitiakitanga in urban spaces Indigenous people’s connection to the natural world differs from place to place. In Aotearoa, New Zealand, Māori connection to nature is often articulated through the concept of kaitiakitanga whilst intertwining concepts of whakapapa, wairua, mana, mauri and place. Kaitiakitanga captures the relationships, narratives and practices that Māori utilise to protect kin of the natural environment as well as Māori communities in general. Over recent decades increase use of kaitiakitanga with respect to resource management has been linked to ideas of guardianship and stewardship, departing from important aspects such as place, whakapapa, intergenerational knowledge, spirituality and resource use. Calls to recognise the diverse ways kaitiakitanga has and can be expressed by Māori have echoed through academic literature, encouraging wider perspectives and application of the concept to develop. This has reinvigorated not only the need for natures protection but also the recognition of cultural knowledges and concepts in practicing kaitiakitanga. 
 
As with most indigenous people, Māori have experienced urbanisation that has spanned across generations of whānau and hapū. Urbanisation has the ability to challenge health outcomes, cultural practices and cultural knowledge, and more importantly, relationships to nature. Growing urbanisation and environmental degradation continue to challenge people and our relationships to nature. There is now a need to understand how urban spaces may also challenge the concepts that encourage connections to nature like kaitiakitanga. Moreover, there is a need to understand if such cultural concepts can become challenged when transient Māori reside in another tribal group’s boundaries. This research provides a deeper analysis of kaitiakitanga by understanding its application within the urban space of Kirikiriroa/Hamilton. From data gathered through a survey, focus groups and interviews, this research project illustrates the experiences of Māori in the urban space who know and practice kaitiakitanga in Kirikiriroa/Hamilton. More importantly, this study posits the integral role of place connection and mana in supporting and shaping kaitiakitanga practices in urban spaces.

The data from participants shows a clear narrative of kaitiakitanga from both local and transient Māori exist and indicates that kaitiakitanga is practiced in accordance with their location and whakapapa to their area of residence. The study has found that kaitiakitanga practices have adapted to suit urban spaces allowing for both transient and local knowledges to exist within the urban space. The key findings of this research show many influences that impact kaitiakitanga practices like the recognition of childhood spaces and experiences, ideas of kinship, cultural knowledges, spirituality, mobility, nature as well as modernisation. Through exploring participants use and knowledge of kaitiakitanga, this research provides a new lens in which to view this concept and bring to the fore, the various experiences and ways that participants connect to place, people, culture and most importantly, nature.

year: 2021