Tribal traditions and practices are integral to iwi identity. From the past to the present, the biggest impact on iwi identity was colonisation and subsequent urbanisation. Urbanisation changed the foundation of identity largely due to the demographic rural-urban shift, effectively creating a distance physically and spiritually for Māori between their place of residence and their traditional tribal turangawaewae. Today a larger proportion of tribal members reside in the main urban centres of New Zealand and Australia. This phenomenon provides an ideal opportunity to explore how iwi identity is maintained in an urban setting – away from the traditional sites of cultural practice. The study, which focuses on Ngāti Awa members residing in Auckland, provided evidence that the foundation of an iwi identity is still heavily reliant on strong iwi-based whānau. The corollary is that, strengthening the tribal knowledge base of whānau residing in urban centres may require new or increased active participation in the customs and practices of their iwi. Regrettably, only three of the ten research participants had an in-depth knowledge of their whakapapa, histories and traditions. However, all the participants indicated the need to become more pro-active in creating and expanding on their knowledge base of iwitanga (including te reo). There was also acknowledgement that urban-based iwi marae and whānau wānanga can provide individuals with the opportunities to learn more about their iwi traditions (and thereby reinforce their sense of tribal identity). Encouragingly, each participant confirmed that identifying as Ngāti Awa was important to them, largely due to the sense of belonging and identity. The study concluded that the sustainability of iwi is reliant on iwi members supporting their iwi regardless of the location of their upbringing.

The aim of this thesis is to develop procedures for the modelling and inversion of teleseismic P and S waveforms which are as flexible as possible. This flexibility is necessary in order to obtain accurate source depth and mechanism estimates for small to moderate size events, such as those that are relevant in the context of monitoring the Comprehensive Nuclear-Test-Ban Treaty (CTBT). ¶ The main challenge for extending source depth and mechanism inversion methods to smaller events is to ensure that sufficiently accurate synthetic seismograms are available for comparison with observed records. An accurate phase-adaptive reflectivity method has therefore been developed, against which the performance of less computationally intensive approximations can be judged. The standard reflectivity method has been modified to allow for different crustal and upper mantle structures at the source and receiver, and the full effects of reverberations and conversions in these structures can be allowed for. Core reflections and refractions can also be included; these phases can become important at certain distance ranges. A slowness bundle approach has been developed, where a restricted slowness integration about the geometric slowness for the direct wave is undertaken at each frequency, allowing accurate results to be obtained whilst avoiding the expense of a full reflectivity technique. ¶ Inversion using the neighbourhood algorithm (NA) is performed for source depth, mechanism and time function, by modelling direct P and S and their surface reflections (pP, sP and pS, sS) at teleseismic distances. Both SV and SH data are exploited in the inversion, in addition to P data, in order to obtain improved constraints on the source mechanism, including any isotropic component. Good results are obtained using a simple generalised ray scheme, however, the use of a flexible derivative-free inversion method means that more accurate synthetics are able to be used in the inversion where appropriate. The NA makes use of only the rank of the data misfits, so that it is possible to employ any suitable misfit criterion. In the few cases where control on the source mechanism is limited, good depth resolution is still usually obtained. ¶The structures near the source and receiver play an important role in shaping the detail of the teleseismic waveforms. Although reasonable results can be achieved with simple synthetics and a standard velocity model, significant improvement can be made by modifying the representation of structure near the source and receiver. In the case of sub-oceanic events it is important to allow for the effects of water reverberations. The crustal structure near the receiver can also have quite a large influence on the waveforms through reverberations and conversions. This is exploited in receiver function inversion, which is again accomplished using the NA approach.

Rural Tourism is increasingly being used as a development strategy to improve the social and economic well being of rural areas. Rural Tourism encompasses a huge range of activities, natural or manmade attractions, amenities and facilities, transportation, marketing and information systems (Sharpley & Sharpley, 1997). Rural tourism is very diverse and fragmented in terms of operational structures, activities, markets and operating environments (Roberts & Hall, 2001, citing Pearce, 1989). Benefits of rural tourism have been expressed as employment growth and broadening a region’s economic base, repopulation, social improvement, and revitalization of local craft (Sharpley, 2000). Governments can play active roles in tourism. In short the literature suggests rural tourism development policy approaches require: regeneration/revitalization, horizontal and vertical integration, interdependence, stewardship/sustainability, mediation, cataclysm, service and welfare provisions, spatiality – awareness, intra and inter regional complementariness, opportunism, realism and quality (Roberts & Hall, 2001). Murphy (1985) proposed a community approach to tourism development which included formation of businesses networks, and the sharing of resources and information. For rural tourism to be successful, collaboration needs to exist amongst entrepreneurs (Wilson et al., 2001). Useful integrated approaches to rural studies include acknowledging the importance of locally controlled agendas to reach centralization, awareness of the benefits for shared ideas and funding developments, and creating appropriate tourism plans for rural areas (MacDonald & Jolliffe, 2003). There are numerous challenges when attempting rural tourism development: the total product package must be sufficient; significant investment may be required; there is the adaption to a service role; the quality of products and services and the availability of skills and resources for effective marketing (Sharpley, 2000). Tourism development requires attractions, promotion, infrastructure and services and hospitality (Wilson et al., 2001, citing Gunn, 1988). The remote Eastern Hokianga area is situated in the Far North (Northland) region of New Zealand. The area has a low population and is sparsely populated presenting an ideal place to relax with an unhurried atmosphere, flourishing fauna and flora, rich in New Zealand history and culture. This is an economically depressed area that is situated in the centre of Northland’s three key tourism icons - The Bay of Islands, the Waipoua Forest, and the top of the North Island. The location of the Eastern Hokianga presents an opportunity to create a tourism destination that will attract travellers frequenting the key tourism icons. To date there has been no research on rural tourism development conducted in the Eastern Hokianga. Although comprehensive research was conducted previously in the Hokianga by the James Henare Maori Research Centre (1999) it was concentrated specifically to the “Maori culture”. This research aims to examine and identify the key challenges of rural tourism development for the Eastern Hokianga through an analysis of rural tourism development approaches, and identifying the social and economic impacts of tourism. Key findings show that the Eastern Hokianga is an undeveloped area and does not fit with the majority of the rural tourism definitions as described in the literature. The area is displaying positive impacts of rural tourism development. The negative impacts are minimal as the Eastern Hokianga is still in the initial development stage of rural tourism. There are many integrated approaches to rural tourism development currently. A strategic approach is occurring with a tourism policy and community involvement in decision making. There is an integration approach with one RTO actively involved in the communities’ tourism association with the local businesses. Two key clustering approaches are being utilized – the Twin Coast Discovery Route and total product packaging. Regeneration is not occurring but was not an issue raised by the community, whereas a financing approach was an identified challenge by Eastern Hokianga businesses. The need to improve accessibility through infrastructure was the second key challenge to rural tourism development. The area was not restricted by the other challenges of government’s role, education / experience and marketing.

<p>In normal image coding the image quality is the same in all parts of the image. When it is known where in the image a single viewer is focusing it is possible to lower the image quality in other parts of the image without lowering the perceived image quality. This master's thesis introduces a coding scheme based on depth perception where the quality of the parts of the image that correspond to out-of-focus scene objects is lowered to obtain data reduction. To obtain further data reduction the method is combined with angular perception coding where the quality is lowered in parts of the image corresponding to the peripheral visual field. It is concluded that depth perception coding can be done without lowering the perceived image quality and that the coding gain increases as the two methods are combined.</p>

This paper describes two methods for constructing a depth map from images. Each method has two stages. First, one or more needle maps are determined using a pair of images. This process employs either the Marr-Poggio-Grimson stereo and shape-from-shading, or, instead, photometric stereo. Secondly, a depth map is constructed from the needle map or needle maps computed by the first stage. Both methods make use of an iterative relaxation method to obtain the final depth map.

The human visual system can extract 3-D shape information of unfamiliar moving objects from their projected transformations. Computational studies of this capacity have established that 3-D shape, can be extracted correctly from a brief presentation, provided that the moving objects are rigid. The human visual system requires a longer temporal extension, but it can cope, however, with considerable deviations from rigidity. It is shown how the 3-D structure of rigid and non-rigid objects can be recovered by maintaining an internal model of the viewed object and modifying it at each instant by the minimal non-rigid change that is sufficient to account for the observed transformation. The results of applying this incremental rigidity scheme to rigid and non-rigid objects in motion are described and compared with human perceptions.

The method described here for recovering the shape of a surface from a shaded image can deal with complex, wrinkled surfaces. Integrability can be enforced easily because both surface height and gradient are represented. The robustness of the method stems in part from linearization of the reflectance map about the current estimate of the surface orientation at each picture cell. The new scheme can find an exact solution of a given shape-from-shading problem even though a regularizing term is included. This is a reflection of the fact that shape-from-shading problems are not ill-posed when boundary conditions are available or when the image contains singular points.

The supply of coral reef fish larvae from the open ocean to reefs is vital for the persistence of local fish populations. Whether larvae are dispersed over hundreds of km or only few km depends on biophysical interactions between larvae and their environment. Relationships between environmental variables, larval swimming behavior, and larval transport were examined for reef fish larvae in the Florida Straits. In a series of research cruises, the upper 100 m of the water column was sampled with plankton nets fishing at four different depths. Variability in the vertical distributions of most larvae was not consistently related to measured environmental variables. Relative densities of larvae were predictably related to sampling depth in five taxa. In seven taxa, more developed larvae were distributed significantly deeper than less developed larvae, revealing ontogenic vertical migrations. In three taxa, vertical distributions varied significantly between day and night, revealing diel migrations. Since the Florida Current was strongest near the surface, observed vertical distributions and migrations resulted in reduced larval transport relative to surface currents. To identify cues involved in regulating vertical distributions, behavioral experiments were conducted with larvae from four reef fish families. All four groups showed significant responses to pressure cues, swimming up in response to high pressure and down in response to low pressure. In two families there was a significant correlation between capture depth and experimental pressure preference, suggesting that larvae use similar behavior to regulate depth in situ. To study horizontal swimming behavior, late-stage larvae of one species were caught in light-traps and observed by SCUBA divers ~1 km offshore of the Florida Keys barrier reef. All larvae swam remarkably straight, but their swimming directions were distributed randomly. A simulation model was used to generate swimming trajectories of longer duration than could be observed directly. Observed and simulated trajectories indicated that horizontal swimming by larvae with or without an external reference frame was important at spatial scales of several km. Overall, some larvae exercised a strong influence on transport, either by vertical or horizontal swimming. Behaviors varied between species and families, highlighting the need for more species-specific data.

The present thesis deals with the development of a new type of dynamic model for metallurgical reactors. It also covers some of the theoretical aspects of steelmaking that is necessary to include in such an application. The thesis consists of modeling work, high temperature experiments and cold model experiments. Two different aspects of slags in the oxygen steelmaking were investigated. In the first study, slag samples were equilibrated with copper at 1923K in order to study their capacities in capturing phosphorous. Some of the samples were liquid-solid mixtures. The solid phases in these samples were identified by SEM analysis. The identified phases were found to agree well with Thermocalc calculations while the amount of solid fractions didn’t. The phosphorous distribution between the different phases was examined. The phosphate capacities of the samples were evaluated. The MgO content didn’t show any appreciable impact on the phosphate capacity. Furthermore the activities of FeO in the liquid slag samples were calculated and were found to deviate positively from ideality. In the second study the foaming height of CaO-SiO2-FeO slags by the reaction with hot metal was investigated. It was found that the foaming height increased with increasing FeO content up to 20-25%. The foaming height was seen to decrease with increased viscosity. The present results indicated that simply using foaming index for converter slag might lead to wrong conclusion. Simulation experiments using cold model at room temperature were conducted. Cold model experiments were carried out in order to study the penetration depth due to an impinging gas jet on the surface of a liquid metal. The liquid alloy Ga-In-Sn was used to simulate steel. And an HCl solution was used to simulate the slag. A comparison with predictions of existing models was made and a new model parameter was suggested. The observation of the movement of metal droplets generated by the gas jet was also made. The low velocity of droplets suggested that the turbulent viscosity played important role and the droplets could have long resident time in the slag. Furthermore a study of the effect of gas flow rate on homogenization and inclusion removal in a gas stirred ladle was carried out. Both industrial trials and cold model experiments were conducted. As an auxiliary tool CFD was used to predict the mixing times and was found to agree well with both the model experiments and industrial data. The increase of flow rate of inert gas would not improve the mixing substantially at higher flow rates. The water model study showed also that the gas flow rate had negligible effect on the rate of inclusion removal. Both the experiments and CFD calculation strongly suggested that low gas flow rate should be applied in the ladle treatment. Lastly a new approach to a dynamic process model of 300 ton BOF converter was made. The main feature was to utilize the velocity vectors obtained by CFD simulation. In the standalone model, the steel melt domain was sliced into 1000 cells. Based on the imported velocity vectors from the CFD calculation, the mass transfer of carbon and phosphorus was calculated taking into account the slag metal reactions. The mass exchange between slag and metal was considered to be dominated by the metal droplet formation due to oxygen jet. The convergence of the model calculation and the promising comparison between the model prediction and the industrial data strongly suggested that the proposed approach would be a powerful tool in dynamic process control. However, more precise descriptions of other process aspects need to be included before the model can be practically employed in a dynamic controlling system. / <p>QC 20120829</p>

Positron-Emission-Tomography (PET) is a modern imaging technique in nuclear medicine providing quantitative 3D distribution of a radioactive tracer substance in the human body. The gamma-detector is the first link in the chain of components that constitutes a PET. It converts incoming radiation into optical light pulses, which are detected by photo multiplier tubes. Here the light is converted into electric pulses, to be further processed by the acquisition electronics. Improving detector sensitivity and resolution is of great value in research and in clinical practice. The focus of this work is to improve the detector to give it time-of-flight (TOF) capabilities, in order to further improve sensitivity, which in turn leads to increased image quality, faster scan time and/or reduced dose exposure for the patient. Image quality has improved over the years, but losses in image quality have been reported for heavy patients, due to increased attenuation, and more dispersed counts over a larger volume. Instrumentation limits are still significant in heavy patient images, but the incorporation of TOF information promises to alleviate some of the limitations. In order to improve the timing resolution of the detector fast photo-multipliers and a novel scheme to extract the event timing trigger from a detector by using the summed dynode signal were investigated. When designing new PET detectors, it is important to have detailed understanding and control of the light sharing mechanisms in the crystal arrays. Therefore it was necessary to perform optical simulations and single crystal light output measurements to derive a model for an LSO block detector. Another way to improve the image quality is to use the depth-of-interaction (DOI) of the gamma ray within the detector. It is shown that a multi-layer phoswich detector comprised of LSO with different decay times and TOF capability, combines the benefits of TOF and DOI in one detector, maximizing the effective sensitivity gain. / At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 7: Submitted.