774 results for 1999

  • Hostile borders on historical landscapes : the placeless place of Andamanese culture

    Pandya, Vishvajit (1999)

    Scholarly text
    Victoria University of Wellington

    This paper is an analysis of meanings attributed to contacts between Jarwas and non-Jarwas in the Andaman Islands. Unlike other Andaman tribal groups, the Jarwas are confined to a government-designated area of 765 square kilometres of forest reserve, which is only a fraction of their former tribal land. Since early colonial occupation, government parties have sought out Jarwas on the west coast of the island they inhabit, bringing them gifts to try to establish friendly relations. On the eastern side of Jarwa territory, on the other hand, the Jarwas raid settlements and occasionally kill settlers and police who venture into their territory. The paper addresses the issue of how the contact event on the eastern side is different in Jarwa eyes from what occurs on the western side. The boundaries are given meanings by the various outsiders and the Jarwas, and these meanings are not fixed. Although contact events are in tended to establish 'friendly' relations with 'hostile' Jarwas, no true relationship of trust and understanding has yet been established. This underlines the fact that meanings are bound by cultural, political and historical contexts.

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  • Wavefront estimation in astronomical imaging.

    Irwan, Roy (1999)

    Doctoral thesis
    University of Canterbury Library

    The challenge in building astronomical telescopes is to obtain the clearest possible image of a distant star, which should appear as a single point. Extended objects, such as galaxies and planets can be regarded as collections of points. However, turbulence in the atmosphere degrades any optical signal that passes through it. The optical effects of the atmospheric turbulence arise from random inhomogeneities in the temperature distribution of the atmosphere. As a consequence of these temperature inhomogeneities, the index of refraction distribution of the atmosphere is random. Plane waves striking the atmosphere from space objects acquire an aberration as they propagate through the atmosphere. The plane wave's surface of constant phase is no longer planar when intercepted by a,n a.stronornica.l telescope. The prnctica.l consequence of a.tmospheric turbulence is that resolution is generally limited by turbulence rather than by optical design and quality of a telescope. There are a number of approaches to solving this problem, ranging from an orbiting telescope (the Hubble Space Telescope), adaptive optics, and post detection processing. The latter approaches have applications to less expensive ground based telescopes and have been the subject of many years of research. Adaptive optics is a general term for optical components whose characteristics can be modified in real time so as to alter the phase of an incident optical wavefront. An adaptive optics system can be used to correct for atmospheric induced distortions. Before any corrections can be applied, however, some measurement must be made of the phase distortions. It is the aim of this study to estimate the degradation of the wavefronts phase. Two approaches to do so are presented. Firstly, through wavefront sensors, which many adaptive optics systems have been devised from. Among them the Shack-Hartmann sensor is the most commonly used. The sensor requires a subdivision of the receiving pupil by means of sub-apertures, wherein the lowestorder deformation of the wavefront phase is estimated. This linearizes the problem of phase retrieval to solving a linear system of equations. A new analysis is presented which differs from previously published work in the estimation of the noise inherent in the centroid calculation used in this sensor. This analysis is supported by computer simulations. Secondly, the nonlinear approach of phase retrieval is discussed. The problem becomes how to relate the phase and magnitude of the Fourier transform. It is thus necessary to estimate the phase distortion in the instrument solely from measurements made at the image plane of the telescope. The process of phase retrieval is then divided into two distinct steps. The expression for the covariance of the phase distortion using a Kolmogorov model for the turbulence is derived first. This covariance is then employed as part of a formal Bayesian estimate of the phase distortion. It is also shown that phase retrieval can be employed as a robust technique for estimating the wavefront distortion using a lenslet array. The results obtained compare favorably with the alternative approach of phase diversity. Furthermore, the introduction of prior information, in the form of statistical information of the distortion, is shown to considerably enhance the success of the phase retrieval especially for very low light levels. A comparative evaluation shows the superiority of phase retrieval to Shack-Hartmann sensing, only if the local maxima are overcome. The principal drawback of phase retrieval is the relatively long computing time required to find the solution when general-purposed computer is used.

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  • Infinite antichains of matroids with characteristic set {p}

    Oxley, J.; Semple, Charles; Vertigan, D.; Whittle, G. (1999)

    Reports
    University of Canterbury Library

    For each prime p, we construct an infinite antichain of matroids in which each matroid has characteristic set {p}. For p=2, each of the matroids in our antichain is an excluded minor for the class of matroids representable over the rationals.

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  • Ring laser dynamics.

    King, Benjamin Thomas (1999)

    Doctoral thesis
    University of Canterbury Library

    The departure of the behaviour of large ring laser gyros from the ideal is examined. A detailed description of the experimental operation of large ring lasers is provided along with several new innovations in equipment layout, data collection and especially in data reduction. The limits on gyro performance due to noise are investigated. A review of literature regarding the fundamental limit placed on gyro resolution is provided. This limit is due to spontaneous emission in the gain medium of the laser and it is demonstrated that our ring lasers approach this quantum limit. Two entirely independent methods for evaluating the quantum noise induced linewidth are demonstrated to agree well. One of the methods, which uses a second order autoregressive model, is able to make accurate linewidth estimates in sub-second gate times. A complex model is proposed which accounts for specific observed light scattering phenomena within a ring laser. This model is compared with dual beam data taken from C-I and is able to describe frequency shifts and waveform distortion accurately. The model also performs favourably when describing locking profiles for low rotation rates and externally induced perimeter modulation. When locked to an external signal the ring laser is found to be an extremely sensitive low frequency vibration detector. The commissioning of a very large (14 m perimeter) prototype ring laser gyro, GO, is described along with a comparison with the smaller ( 4 m perimeter) gyros C-I and C-II. This prototype has proven to be an invaluable testing ground for designs and techniques to be used on a proposed high precision 16 m perimeter gyro named the Grossring (G).

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  • Final report for BOP Fertiliser Ltd. : transportation, marketing, process design and costing for the commercialisation of granular reactive phosphate rock

    Ferris, Tim (1999)

    Masters thesis
    University of Canterbury Library

    This report was completed to determine the commercial feasibility of granular Reactive Phosphate Rock (RPR) as a fertiliser, and the requirements needed to bring it to market. Recommendations based on this report are as follows: • Redesign the existing Morrinsville plant • Change the name of the final product to something that is not directly associated with RPR, ie Gradual Delivery Phosphate • Convince the sales representatives in the ability of the new granular RPR • Employ a dedicated representative to target the forest and organic markets • Sell granular RPR for $210 per tonne ex works from year one • Consider adding extra nutrients into granular RPR for the Forestry market • Use marketing to current markets extensively • Appoint a Program Director for the implementation of granular RPR • Offer bulk discounts and special deals to bring in customers for the initial sale of RPR.

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  • Page turning : score automation for musicians

    McPherson, John R. (1999)

    Reports
    University of Canterbury Library

    This report examines various aspects of the use of computers for the purpose of displaying sheet music for musicians. The main focus is on the layout of the displayed music and methods that can be used to simulate physical page turning to provide new information for the musician. The techniques that may be used to update the field of view depend on factors such as the amount of information to be displayed at any one time, from which direction the new information should come, various monitor attributes such as size, brightness and resolution, and how the transition should be made between the current view and the next view. A small feasibility study was conducted on a group of musicians to determine which of the page turning concepts under consideration should undergo further evaluation for potential benefit. The results of this study suggest that a few of the identified techniques could be withdrawn from consideration. However, individual preferences appear to have a large effect in the usability of the different methods.

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  • Calendar 1999

    Victoria University of Wellington (Wellington, N.Z.) (1999)

    Scholarly text
    Victoria University of Wellington

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  • Balancing security and accountability : SIS legislation and recent amendments

    Barrie, Kirstin. (1999)

    Scholarly text
    Victoria University of Wellington

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  • Ocean floor resources : the wider effects of fisheries management

    Anton, Katherine. (1999)

    Scholarly text
    Victoria University of Wellington

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  • Playing by the new rules : a critique of the 1996 standing orders in New Zealand's House of Representatives

    Gifford, Susan, 1951- (1999)

    Scholarly text
    Victoria University of Wellington

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  • Disclosure : the right to be informed of the risks inherent in medical treatment

    Baber, Catherine Hannah. (1999)

    Scholarly text
    Victoria University of Wellington

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  • Electromagnetic radiation, trespass to land, and the Shelfer test

    Campbell, Fiona, 1977- (1999)

    Scholarly text
    Victoria University of Wellington

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  • Public law models for the implementation of paid parental leave

    Williams, Anthea. (1999)

    Scholarly text
    Victoria University of Wellington

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  • Utilitarianism vs. individual rights : has the Mental Health (Compulsory Assessment and Treatment) Act 1992 struck the right balance?

    Warner, Samantha Eleanor. (1999)

    Scholarly text
    Victoria University of Wellington

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  • A trust is a trust, of course of course? : the Limitation Act 1950, Section 21 and the constructive trust

    Barsi, Mauro. (1999)

    Scholarly text
    Victoria University of Wellington

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  • Adopting reality : the case for legal recognition on Maori customary adoption in New Zealand

    Thompson, Rhonda. (1999)

    Scholarly text
    Victoria University of Wellington

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  • Protecting biodiversity on private land and property rights in New Zealand

    Meo, Tristan. (1999)

    Scholarly text
    Victoria University of Wellington

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  • Giving, withdrawing and dispensing with consents before and after the Adoption Act 1955 : history, criticisms and options for reform

    Hutchison, Megan Louise. (1999)

    Scholarly text
    Victoria University of Wellington

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  • The Pinochet judgement : new accountability for old dictators

    Murphy, Sarah L. (1999)

    Scholarly text
    Victoria University of Wellington

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  • The prima facie exclusionary rule : a time for reflection

    Mason, Michelle A. (1999)

    Scholarly text
    Victoria University of Wellington

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