title: Object orientation without  extending Z

authors: Utting, Mark

abstract: The good news of this paper is that without extending Z,
we can elegantly specify object-oriented systems, including encapsulation,
inheritance and subtype polymorphism (dynamic dispatch). The
bad news is that this specification style is rather different to normal
Z specifications, more abstract and axiomatic, which means that it is
not so well supported by current Z tools such as animators. It also enforces
behavioural subtyping, unlike most object-oriented programming
languages. This paper explains the proposed style, with examples, and
discusses its advantages and disadvantages.

text: Object orientation without  extending Z The good news of this paper is that without extending Z,
we can elegantly specify object-oriented systems, including encapsulation,
inheritance and subtype polymorphism (dynamic dispatch). The
bad news is that this specification style is rather different to normal
Z specifications, more abstract and axiomatic, which means that it is
not so well supported by current Z tools such as animators. It also enforces
behavioural subtyping, unlike most object-oriented programming
languages. This paper explains the proposed style, with examples, and
discusses its advantages and disadvantages.

year: 2002-12-01

title: A reduced magnetohydrodynamic model of coronal heating in open magnetic regions driven by reflected low-frequency waves

authors: Oughton, Sean

subjects: MHD

abstract: A reduced magnetohydrodynamic (RMHD) description is employed to examine a suggestion made by W. H. Matthaeus and colleagues in 1999 that coronal heating might be sustained by a cascade of low-frequency MHD turbulence. Here RMHD simulations show that the low-frequency cascade to high transverse wavenumbers can be driven by an externally maintained flux of low-frequency propagating Alfvén waves, in combination with reflection caused by an inhomogeneous background medium. The simulations show that the suggestions made previously on the basis of a phenomenology are indeed realizable. In addition, the effect is seen to sensitively depend on the presence of reflection, as the background turbulence level needed to maintain the cascade can be sustained only when reflection is imposed. The steady level of turbulence is insensitive to the initial seed turbulence level (provided it is nonzero). Consequences of this model for realistic models of coronal heating in open field-line regions are discussed.

text: A reduced magnetohydrodynamic model of coronal heating in open magnetic regions driven by reflected low-frequency waves A reduced magnetohydrodynamic (RMHD) description is employed to examine a suggestion made by W. H. Matthaeus and colleagues in 1999 that coronal heating might be sustained by a cascade of low-frequency MHD turbulence. Here RMHD simulations show that the low-frequency cascade to high transverse wavenumbers can be driven by an externally maintained flux of low-frequency propagating Alfvén waves, in combination with reflection caused by an inhomogeneous background medium. The simulations show that the suggestions made previously on the basis of a phenomenology are indeed realizable. In addition, the effect is seen to sensitively depend on the presence of reflection, as the background turbulence level needed to maintain the cascade can be sustained only when reflection is imposed. The steady level of turbulence is insensitive to the initial seed turbulence level (provided it is nonzero). Consequences of this model for realistic models of coronal heating in open field-line regions are discussed.

year: 2001

title: Riperata kahutia: a woman of mana

authors: Nikora, Shelley Aroha

subjects: Riperata Kahutia

abstract: Riperata Kahutia is widely remembered as a leader in the history of Tūranganuiā-
Kiwa, who fought to retain and repossess land during the difficult times of the
1860's. During this period of rapid social change and political upheavals resulting
in injustices, the exercise of rangatiratanga took many forms. Responses to
change covered a wide spectrum and there was no 'right' way of doing things,
simply leaders making decisions on the basis of what they and their people
thought at the time were best. Riperata utilised the law as a means of retaining
the land and the mana of her people. While her status as a rangatira was never in
doubt, innuendo surfaced suggesting she may have received more land entitlement
than she was qualified for.
The activities by Riperata may have been different from other leaders but the
purpose was the same: to preserve the people and the land. Her strategies for
doing so, based on her inherited mana and upbringing, her knowledge of local iwi
traditions, her acquisition of new skills introduced by Pākehā and her innovative
approaches to exercising her rangatiratanga, make her a worthwhile study.
This thesis will support the viewpoint that Riperata Kahutia acted on behalf of her
people and for the good of her people. It will be argued Riperata was a visionary
who embraced the changes imposed upon a society enduring the consequences of
colonisation. A major objective is to dispel suggestions she embellished her
rights.

text: Riperata kahutia: a woman of mana Riperata Kahutia is widely remembered as a leader in the history of Tūranganuiā-
Kiwa, who fought to retain and repossess land during the difficult times of the
1860's. During this period of rapid social change and political upheavals resulting
in injustices, the exercise of rangatiratanga took many forms. Responses to
change covered a wide spectrum and there was no 'right' way of doing things,
simply leaders making decisions on the basis of what they and their people
thought at the time were best. Riperata utilised the law as a means of retaining
the land and the mana of her people. While her status as a rangatira was never in
doubt, innuendo surfaced suggesting she may have received more land entitlement
than she was qualified for.
The activities by Riperata may have been different from other leaders but the
purpose was the same: to preserve the people and the land. Her strategies for
doing so, based on her inherited mana and upbringing, her knowledge of local iwi
traditions, her acquisition of new skills introduced by Pākehā and her innovative
approaches to exercising her rangatiratanga, make her a worthwhile study.
This thesis will support the viewpoint that Riperata Kahutia acted on behalf of her
people and for the good of her people. It will be argued Riperata was a visionary
who embraced the changes imposed upon a society enduring the consequences of
colonisation. A major objective is to dispel suggestions she embellished her
rights.

year: 2009