title: New foundations for Z

authors: Henson, Martin C.

subjects: computer science

abstract: We provide a constructive and intensional interpretation for the specification language Z in a theory of operations and kinds T. The motivation is to facilitate the development of an integrated approach to program construction. We illustrate the new foundations for Z with examples.

text: New foundations for Z We provide a constructive and intensional interpretation for the specification language Z in a theory of operations and kinds T. The motivation is to facilitate the development of an integrated approach to program construction. We illustrate the new foundations for Z with examples.

year: 1998-03

title: Seismically-induced down-sagging structures in tephra layers (tephra-seismites) preserved in lakes since 17.5 cal ka, Hamilton lowlands, New Zealand

authors: Kluger, Max O.

abstract: We analysed numerous soft-sediment deformation structures (SSDSs) identified in seven unconsolidated, up to 8-cmthick, siliceous tephra layers that had been deposited in ~35 riverine-phytogenic lakeswithin the Hamilton lowlands, northern North Island, New Zealand, since 17.5 calendar (cal) ka BP. Based on sediment/tephra descriptions and X-ray computed tomography scanning of cores taken from ten lakes, we classified these SSDSs into elongated load structures (i.e., down-sagging structures) of different dimensions, ranging from millimetre- to decimetre-scale and centimetre-long dykes. Down-sagging structures were commonly manifested as intrusions of internal tephra beds of very fine to medium sand into underlying organic lake sediments.
The tephra layers commonly exhibited an upper silt bed, which was not directly affected by deformation. Dry bulk density and grain size distribution analyses of both the organic lake sediment and the internal tephra beds provided evidence for the deformation mechanism of down-sagging structures and their driving force:
the organic lake sediment and the upper silt bed are less liquefiable, whereas the very fine to medium sand internal tephra beds are liquefiable. The tephra layers and encapsulating organic lake sediments formed three layer (a–b–a) density systems, where ‘a’ denotes the sediment unit of lower density. We infer that downward directed deformation was favoured by the a–b–a density system with the upper, less-liquefiable, silt bed within the tephra layer preventing upward intrusion during the liquefaction process. The spatial distribution and ages of SSDSs within the lakes provided some evidence that liquefaction of the older tephra layers, i.e., Rerewhakaaitu, Rotorua, and Waiohau tephras, deposited 17.5, 15.6, and 14 cal ka BP, respectively, was triggered by a seismic source to the northeast of the Hamilton lowlands (i.e., Kerepehi and/or Te Puninga faults). In contrast, the liquefaction of the younger tephra layers, i.e., Opepe, Mamaku, and Tuhua tephras, deposited 10.0, 8.0, and 7.6 cal ka BP, respectively, may have been triggered by movement on local faults within the Hamilton lowlands, namely the Hamilton Basin faults, or by distant faulting at the Hikurangi subduction margin east of North Island.

text: Seismically-induced down-sagging structures in tephra layers (tephra-seismites) preserved in lakes since 17.5 cal ka, Hamilton lowlands, New Zealand We analysed numerous soft-sediment deformation structures (SSDSs) identified in seven unconsolidated, up to 8-cmthick, siliceous tephra layers that had been deposited in ~35 riverine-phytogenic lakeswithin the Hamilton lowlands, northern North Island, New Zealand, since 17.5 calendar (cal) ka BP. Based on sediment/tephra descriptions and X-ray computed tomography scanning of cores taken from ten lakes, we classified these SSDSs into elongated load structures (i.e., down-sagging structures) of different dimensions, ranging from millimetre- to decimetre-scale and centimetre-long dykes. Down-sagging structures were commonly manifested as intrusions of internal tephra beds of very fine to medium sand into underlying organic lake sediments.
The tephra layers commonly exhibited an upper silt bed, which was not directly affected by deformation. Dry bulk density and grain size distribution analyses of both the organic lake sediment and the internal tephra beds provided evidence for the deformation mechanism of down-sagging structures and their driving force:
the organic lake sediment and the upper silt bed are less liquefiable, whereas the very fine to medium sand internal tephra beds are liquefiable. The tephra layers and encapsulating organic lake sediments formed three layer (a–b–a) density systems, where ‘a’ denotes the sediment unit of lower density. We infer that downward directed deformation was favoured by the a–b–a density system with the upper, less-liquefiable, silt bed within the tephra layer preventing upward intrusion during the liquefaction process. The spatial distribution and ages of SSDSs within the lakes provided some evidence that liquefaction of the older tephra layers, i.e., Rerewhakaaitu, Rotorua, and Waiohau tephras, deposited 17.5, 15.6, and 14 cal ka BP, respectively, was triggered by a seismic source to the northeast of the Hamilton lowlands (i.e., Kerepehi and/or Te Puninga faults). In contrast, the liquefaction of the younger tephra layers, i.e., Opepe, Mamaku, and Tuhua tephras, deposited 10.0, 8.0, and 7.6 cal ka BP, respectively, may have been triggered by movement on local faults within the Hamilton lowlands, namely the Hamilton Basin faults, or by distant faulting at the Hikurangi subduction margin east of North Island.

year: 2023-03

title: Computational thinking for young indigenous learners in New Zealand

authors: Fox-Turnbull, Wendy

subjects: authentic technological practice

abstract: This article presents the findings from a study aimed to investigate how the computational thinking aspect of digital technologies can be embedded authentically into students’ technological practice. The project explored teaching and learning computational thinking in context and particularly focus on technological needs and practice for young Māori learners.
There is recognition internationally about the need for digital technologies within the curriculum. Computational thinking is a critical component of this and is defined as an approach to problem-solving, designing computer systems, and understanding related human behaviours, while drawing on fundamental ideas of computing. Therefore, it is critical that all students acquire computational thinking skills. Technology practice is most successful when embedded within authentic contexts, thus this paper presents a study that facilitated the learning of two concepts of computational thinking: sequencing and orientation within culturally embedded technology practice. The study’s vision is to assist mainstream Māori learners from low socio-economic backgrounds to develop an understanding of related concepts of computational thinking. The research design drew on Māori values and practice that situates learning within authentic Māori contexts. Kaupapa Māori pedagogies were used in our design-based intervention programme to achieve the research goal. The focus of the project was to improve digital technologies learning outcomes to ensure Māori tamariki (children) see themselves as comfortably situated in a digital world.

text: Computational thinking for young indigenous learners in New Zealand This article presents the findings from a study aimed to investigate how the computational thinking aspect of digital technologies can be embedded authentically into students’ technological practice. The project explored teaching and learning computational thinking in context and particularly focus on technological needs and practice for young Māori learners.
There is recognition internationally about the need for digital technologies within the curriculum. Computational thinking is a critical component of this and is defined as an approach to problem-solving, designing computer systems, and understanding related human behaviours, while drawing on fundamental ideas of computing. Therefore, it is critical that all students acquire computational thinking skills. Technology practice is most successful when embedded within authentic contexts, thus this paper presents a study that facilitated the learning of two concepts of computational thinking: sequencing and orientation within culturally embedded technology practice. The study’s vision is to assist mainstream Māori learners from low socio-economic backgrounds to develop an understanding of related concepts of computational thinking. The research design drew on Māori values and practice that situates learning within authentic Māori contexts. Kaupapa Māori pedagogies were used in our design-based intervention programme to achieve the research goal. The focus of the project was to improve digital technologies learning outcomes to ensure Māori tamariki (children) see themselves as comfortably situated in a digital world.

year: 2024