6,494 results for Conference item

  • RSA-Based Undeniable Signatures for General Moduli

    Galbraith, Steven; Mao, W; Paterson, KG (2002)

    Conference item
    The University of Auckland Library

    Gennaro, Krawczyk and Rabin gave the first undeniable signature scheme based on RSA signatures. However, their solution required the use of RSA moduli which are a product of safe primes. This paper gives techniques which allow RSA-based undeniable signatures for general moduli

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  • Supersingular Curves in Cryptography

    Galbraith, Steven (2001)

    Conference item
    The University of Auckland Library

    Frey and R??ck gave a method to transform the discrete logarithm problem in the divisor class group of a curve over F q into a discrete logarithm problem in some finite field extension F q k . The discrete logarithm problem can therefore be solved using index calculus algorithms as long as k is small. In the elliptic curve case it was shown by Menezes, Okamoto and Vanstone that for supersingular curves one has k ??? 6. In this paper curves of higher genus are studied. Bounds on the possible values for k in the case of supersingular curves are given which imply that supersingular curves are weaker than the general case for cryptography. Ways to ensure that a curve is not supersingular are also discussed. A constructive application of supersingular curves to cryptography is given, by generalising an identity-based cryptosystem due to Boneh and Franklin. The generalised scheme provides a significant reduction in bandwidth compared with the original scheme.

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  • Sustainable Economic Strategies

    Ingham, Jason (2001)

    Conference item
    The University of Auckland Library

    This document seeks to objectively compile available literature and report emerging issues considering aspects of sustainable economic development. In conducting this exercise it has become evident that both sustainable development and globalisation are topics whose meaning and impact have yet to be widely understood and endorsed within New Zealand. Every effort has been made to capture the nature of the current debate surrounding these issues, and in general the content of the various viewpoints has been presented verbatim with referencing, using internet references where available. Quite deliberately the author has attempted to avoid emphasising a single viewpoint, while taking care to compile a coherent report addressing the topic at hand. Definitions of economic growth and sustainable economic development are first considered, including comments on environmental and indigenous culture implications and the notion of triple bottom line reporting. This is followed by a brief account of New Zealand???s past economic performance. Details of New Zealand???s decline in prosperity with respect to its OECD contemporaries are considered, and the influence of the economic reforms of the late 1980???s and early 1990???s is discussed. Next the policies initiated by the current Labour-Alliance government are considered. These policies were designed to close the gap between the prosperous and less prosperous members of New Zealand???s society, emphasising the need for social cohesion and policies that provide benefits to all. The current absence of a national vision is discussed, and a proposed vision for New Zealand???s future is presented, embracing both social and economic considerations, and taking into account Governments stated vision. It is suggested that in the absence of an existing vision and consensus on the parameters that New Zealanders deem most appropriate to quantify their comparative prosperity, it is premature to present prescribed performance goals. Nevertheless, candidate outcomes for a vision of New Zealand are presented. As prelude to the debate, issues surrounding personal perspectives on the relative priority afforded to the economy, the environment, and societal factors are revisited. Recognising the intimate relationship between the knowledge society and global trade in the internet era, the growing debate surrounding emerging aspects of globalisation are reviewed. Finally, a suite of candidate strategies for sustainable economic development is formulated. It is emphasised that the validity of these strategies is less important than their success in provoking thought and dialogue on issues currently facing New Zealand, and how as a nation we will retain or elevate our relative level of prosperity. The central pillar of the strategy set is the development of a balanced scorecard for the nation, capturing the dimensions of growth economy, talent nation, knowledge society, cohesive community and healthy environment. For each dimension a readily quantifiable performance parameter and recommended performance target are provided. Extending from this scorecard, a strategy for public policy transformation to create a knowledge economy is presented. It is proposed that the key imperatives are for Government to reduce the bureaucracy, transform the business environment, and assemble a national economic development agency. In support of this public policy transformation, it is recognised that New Zealand businesses must transform themselves in order to effectively participate in the knowledge economy. Imperatives for change include the need to celebrate business success, better develop and exploit a national brand, focus on growth-oriented talent management, participate in solving New Zealand???s structural problems, change the product/service mix, lift the focus on innovation, make greater use of niche markets, economic development zones, and cluster, and participate in new capital formation.

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  • Pheromones for pest management and eradication of invasive species

    Suckling, David (2014)

    Conference item
    The University of Auckland Library

    Surveillance is a key component to pest management and biosecurity and the availability of attractants for certain insects has revolutionised our ability to intervene against them. In fact, the improvement in success of eradication when attractants are available is more than 20-fold, according to a recent global study. Populations of such invasive species with urticating hairs and a wide host range as tussock moths or processionary moths can be controlled or eradicated when these tools are available for delimitation and suppression, and in New Zealand several eradication programs have been operated successfully. Examples are whitespotted tussock moth (Lymantriidae), painted apple moth (Lymantriidae), fall webworm (Arctiidae), Hokkaido gypsy moth (Lymantriidae). In other cases, it has not been possible to eradicate the organism, such as the defoliating gum leaf skeletoniser (Nolidae), an outbreak species in Australia and now widely dispersed in New Zealand. The identification and deployment of this insect illustrates the surveillance paradigm well. Beyond applications in surveillance, it is also possible to consider aerial application of mating disruption with various formulations, such as those recently compared in a New Zealand study on a tortricid (microencapsulations, SPLAT and a bioflake) with the ground application of a polyethylene tubing dispesnser. Pheromones can also be envisaged to be developed in other new ways, from mobile mating disruption to ant trail pheromone disruption. New trapping and surveillance tools and new concepts for biosecurity from can widen the tool kit we need to combat invasive species. A deep knowledge of chemical ecology is needed to face this challenge.

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  • Damage and vulnerability analysis of URM churches after the Canterbury earthquake sequence 2010-2011

    Cattari, S; Ottonelli, D; Pinna, M; Lagomarsino, S; Clark, W; Giovinazzi, S; Ingham, Jason; Marotta, A; Liberatore, D; Sorrentino, L; Leite, J; Lourenco, PB; Goded, T (2015-07-09)

    Conference item
    The University of Auckland Library

    The Canterbury earthquake sequence, in 2010-2011, has highlighted once again the vulnerability of monumental structures, in particular churches, and the importance of reducing their risk from an economic, cultural and social point of view. Within this context, detailed analysis is reported of the earthquake-induced damage to a stock of 48 unreinforced masonry churches located in the Canterbury Region and the vulnerability analysis of a wider stock of 293 churches located all around New Zealand. New tools were developed for the assessment of New Zealand churches. The computation of a new damage grade is proposed, assessed as a proper combination of the damage level to each macroelement, as a step towards the definition of a New Zealand specific damage survey form. Several vulnerability indicators were selected, which are related to easily detectable structural details and geometric dimensions. The collection of such data for the larger set of churches (293) constitutes a useful basis for evaluating the potential impact of future seismic events.

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  • Approaches to design of shallow foundations for low-rise framed structures

    Pender, Michael; Wotherspoon, Liam; Ingham, Jason; Carr, AJ (2006)

    Conference item
    The University of Auckland Library

    We compare two approaches to the design of the foundations for low-rise reinforced concrete framed structures founded on discrete shallow footings. The underlying soil is stiff clay. The first approach considers the foundations separately from the structure, uses an equivalent static method to estimate foundation actions, and then proportions the foundations to have adequate bearing strength under these actions. The second considers an integrated model of the structure-foundation system. Computer modelling was undertaken using Ruaumoko (Carr 2004), a nonlinear dynamic structural analysis program. The framed structures on shallow foundations, connected with tie beams (not considered part of the foundation) were analysed and the effects of structural yielding, nonlinear soil behaviour and foundation uplift were determined. Yielding and uplift characteristics of the foundations were modelled by adapting available structural models in the software. The main conclusion from the paper is that the sophistication of the integrated computer model gives enhanced understanding of the structure-foundation system.

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  • A compact direct-drive linear synchronous motor with muscle-like performance

    Ruddy, Bryan; Hunter, IW (2013)

    Conference item
    The University of Auckland Library

    We present the design of a novel direct-drive linear permanent magnet synchronous motor with a high continuous-duty force-to-mass ratio. We use an analytical electromagnetic model to find optimal dimensions for a new magnet configuration, comprising nested tubular Halbach arrays. We further use the analytical model to map out the design space for these motors, and investigate possible designs for motors with muscle-like force production. We then describe the design of a 100 g-scale motor based on the optimization, with water cooling and a lightweight structure. Experimental results suggest that this motor is capable of over 140 N/kg continuous force production, and demonstrate that it can be used for positioning at over 1 m/s and with 40 g acceleration unloaded.

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  • Modelling the damage to the Manchester Courts building in the Canterbury earthquakes sequence

    Wang, Guojue; Pender, Michael; Ingham, Jason (2015-07-09)

    Conference item
    The University of Auckland Library

    Seismic assessment of the Manchester Courts building is presented. This building was demolished following severe damage that resulted from the magnitude 7.1 Darfield earthquake (Canterbury, NZ) on 4 September 2010, amongst widespread objection from heritage supporters who believed that this historic building could be adequately reinstated. Finite element (FE) analysis was used to undertake a performance-based assessment using time-history analyses, and the accuracy of the model was validated by comparing the simulated results with benchmark experimental data and observed damage. The finite element model utilised two-dimensional (2D) elements in three-dimensional (3D) space and the macro modelling method was used.

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  • (Engaging or avoiding) Responsibility through Reflexive Practices

    Callagher, Lisa; Hibbert, P; Kim, Hee; Siedlok, Franciszek; Windahl, Charlotta (2015-07-02)

    Conference item
    The University of Auckland Library

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  • Resistance and challenge: the shaping of indigenous entrepreneurship, a Maori context.

    Kawharu, Merata; Tapsell, P; Woods, Christine (2013)

    Conference item
    The University of Auckland Library

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  • Heavy syllables in Gitksan

    Brown, Jason (2015)

    Conference item
    The University of Auckland Library

    Very little attention in the existing literature has been devoted to the prosodic structure of Gitksan. Recent work on stress, however, has opened a productive discussion about syllable weight. This paper uses these insights to further the discussion about possible moraic structures, and isolates a difference in how weight is assigned to consonants in stress vs. in other types of prosodic morphology, such as reduplication and word minimality. The patterns that emerge are similar to the behavior of heavy syllables in other languages, but with some key differences.

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  • Computer modelling retrospective on Wairakei and Ohaaki

    OSullivan, Michael; Clearwater, Emily; Yeh, Angus; O'Sullivan, John; Shinde, A; Newson, JA; Zarrouk, Sadiq; Mannington, WI (2015-04-20)

    Conference item
    The University of Auckland Library

    Our modelling studies of the Wairakei and Ohaaki geothermal fields have been ongoing for more than 30 years and it is now possible to check back on the predictions made from early studies carried out in the 1990s and early 2000s and determine how well the predictions made by those models compare with reality. There are several problems with a retrospective assessment of the 1990s and early 2000s models. The most significant is that the future scenarios considered then are different from the actual production and injection strategies followed. We overcame this difficulty by using the actual production /injection history with the old models. In general the models perform quite well in matching the production history but in both cases they are too conservative and the actual performance of Wairakei and Ohaaki has been better than that predicted by models from the late 1990s or early 2000s. In both cases the number of make-up wells used in the original future scenarios turned out to be more than have actually been required The main discrepancies arise because of the development of new and/or deeper production zones, not included in the old models. In some cases, e.g. the shallow steam zone at Te Mihi (Wairakei), the permeability has turned out to be even higher than the high value used in the old model and production has continued past the point when the old model predicts failure should occur due to a large pressure decline.

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  • The effect of interface material on the dynamic behavior of free rocking blocks

    ElGawady, Mohamed; Ma, Tsun Ming Quincy; Butterworth, John; Ingham, Jason (2006)

    Conference item
    The University of Auckland Library

    The rocking response of ten rigid blocks with aspect ratios ranging from 0.7 to 5 was investigated, with a particular focus on the possible effect of interface material. The blocks were allowed to rock on timber, steel, reinforced concrete, and rubber bases. The blocks consisted of either masonry bricks arranged to give the required aspect ratio or a single reinforced concrete block having the required aspect ratio. Preliminary results showed that both aspect ratio and interface material exerted significant influence on the rocking response. In addition, the rocking characteristics of the blocks were calculated using simple mathematical models based on fundamental principles of mechanics. The models were generally found to overestimate the rotation amplitudes and periods.

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  • Effect of Flexibility on the Performance of Polymeric Foams in Sandwich Construction Hull Panelling Under Slamming

    Allen, Thomas; Battley, Mark (2015-07)

    Conference item
    The University of Auckland Library

    Prediction of damage to hull panelling during dynamic slamming impacts is critical in the design of safe vessels. Modern composite hull design often utilises high ductility polymeric foams in a sandwich construction for regions likely to undergo slamming during operation. The nature of these constructions, which have large failure strains compared with metallic constructions, can result in panelling that undergoes significant deformations during slamming impacts. These deformations have been shown to affect the applied pressure distribution and magnitude. This paper addresses how the stress state in the core varies as a result of flexibility in hull panelling. Experiments have been undertaken on a range of sandwich construction panels using the custom Servo-hydraulic Slam Testing System (SSTS). Rectangular glass-fibre/epoxy skin sandwich panel specimens of dimensions 1030??5 mm x 540??05 mm were manufactured using a resin infusion process with Gurit M130 as their core material. The thickness of the GRP skins was varied between panels. Testing has been undertaken on the panels at 10?? with vertical impact velocities between 1.0 m/s and 9.5 m/s. The panel???s integrity is monitored throughout the impacts using bi-axial resistive strain gauges. The velocities at which both yield and ultimate failure occur have been identified. Variations in both the yield and failure speeds of the panels have been observed experimentally. These variations are linked to the varying levels of deformation between the panels resulting in different pressure distributions. These findings highlight the necessity to consider both strength and stiffness in scenarios where fluid-structure interaction may be present as a change in stiffness may lead to an inadvertent change in effective strength.

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  • Tensile, compressive and impact performance of high volume-fraction resin transfer moulded flax and glass fibre epoxy laminates for sporting applications

    Ling, Henry; Battley, Mark; Allen, Thomas (2015-07)

    Conference item
    The University of Auckland Library

    Flax fibres have shown promise as a suitable ???green??? alternative to glass fibres. Their specific strength and specific stiffness is similar to that of E-glass fibres. However, to date, composites manufactured with flax fibres have typically had lower specific strengths than glass-fibre composites. There is also only limited information available on the performance of high volume-fraction (>50%) flax/epoxy composites, which is the range of volume-fractions likely to be used in high performance applications. This study compares the quasi-static tensile and compressive mechanical properties and dynamic impact performance of high volume-fraction flax/epoxy and glass-fibre laminates manufactured using Resin Transfer Moulding (RTM). Panels were manufactured from woven 150gsm flax and 285gsm glass fibres with Gurit Prime 20LV Epoxy resin. Two different comparisons were made. The first was between 4mm thick flax/epoxy and glassfibre panels each with 20 layers and hence the same number of interfaces between lamina. These interfaces are where delamination can occur, so are important for impact performance. The second case compared two panels having the same areal weight; a 6 mm flax/epoxy panel and a 4 mm glassfibre panel with 32 and 20 plies respectively. As flax fibres have a lower density than glass fibres, panels of the same weight are thicker which may provide an advantage for out-of-plane properties, such as impact and flexural strength. Results from this study indicate that flax-fibre laminates, even on a specific basis, have a lower tensile, compressive and impact performance than thickness or weight equivalent glass-fibre laminates. Potential improvement may be seen by combining glass and flax fibres into a hybrid laminate to leverage the sustainability and lower density of flax fibres.

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  • Biaxial pseudodynamic tests of a post-tensioned rocking column with externally mounted energy dissipators

    Gultom, R; Ma, Tsun Ming Quincy (2015-04-10)

    Conference item
    The University of Auckland Library

    The effects of multi-directional loading during earthquake excitation are often overlooked in laboratory experiments due to the high cost and setup complexity. However many structural failures are caused by the combined effect of multi-directional loading. Currently, there is no definitive guidance on the effects of different displacement tracking objectives on the results of multi-directional physical earthquake simulations. This study tested a post-tensioned rectangular rocking concrete column with externally mounted energy dissipators pseudodynamically subjected to simultaneous biaxial loading. The setup emulated bidirectional earthquake ground motion. The study focused on the effects of different displacement tracking strategies in pseudodynamic tests. Experiments found that different displacement tracking strategies gave rise to additional plastic deformations of the specimen and consequently resulted in appreciable differences in the time history predictions both in amplitude and phase lag. Interestingly, the experiments revealed a design deficiency of the externally mounted energy dissipators. The dissipators were shown to be susceptible to buckle during bidirectional loading, a phenomenon that has been missed in previous earthquake simulations.

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  • A relevant mandate for the EMRIP: an insider???s perspective

    Charters, Claire (2015-04-26)

    Conference item
    The University of Auckland Library

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  • Expanding the mandate of the Expert Mechanism on the Rights of Indigenous Peoples

    Charters, Claire (2015-02-20)

    Conference item
    The University of Auckland Library

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  • Growth Opportunity Development in High-Tech Entrepreneurs: Business Objectives, Human Resources Orientation and Competitive Advantage

    Fath, Benjamin; Fiedler, Antje; Simmons, Glenn; Whittaker, H; Byosiere, P (2014-09-17)

    Conference item
    The University of Auckland Library

    The relationship between business objectives, human resources orientations, growth limitations and competitive advantage is investigated for four past-future growth opportunity types (exhausted, turnaround, maturing, continuing) for Japanese High-Tech entrepreneurs. The results indicate that entrepreneurs perceiving continuing growth opportunities show clear all-embracing relationships between business objectives, human resources orientations and competitive advantage with a thoughtful concern for growth limitations. Firms characterized by exhausted, turnaround and maturing growth opportunities show less comprehensive relationships among the four constructs. Concluding, we find that the past performance is driven by a relationship between the business objectives of the founder and competitive advantage, while the perceived future growth opportunity is largely determined by the strength of the relationship between the founder???s business objectives and HRM orientations.

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  • A Penrosian approach to innovative, sustainable fisheries

    Simmons, Glenn (2010-03-13)

    Conference item
    The University of Auckland Library

    Sustainability of fisheries, both at a macro level and at the level of individual firms, is of huge significance economically and socially to many countries. Changes in value chains and in particular the growth of offshoring compounds sustainability and socio-economic issues. New Zealand has the world???s fourth largest fisheries exclusive economic zone (EEZ), yet it ranks only 25th in terms of fisheries exporting nations, with exports amounting to a mere 1.2 percent of the total global fisheries trade (MFish, 2010). What???s more, the fisheries industry is characterised by plant closures, job losses and, according to Stringer (2010), increasingly the offshoring of value-added processing and export of related technology, particularly to China. This erodes the industry???s technological base which is necessary to sustain innovation. This study applies a Penrosian perspective to the New Zealand fisheries industry. For Penrose (1959), firms use a combination of external and internal resources to grow, but growth is limited essentially by the capacities of management, and whether entrepreneurial managers see opportunities for growth arising from other possible uses of its resources. This approach has been further refined by Teece in recent years (e.g. Teece, 2009). The framework derived from these studies encompasses the entrepreneur, firm and industry levels of analysis. Using Penrosian mapping, I look at the largest firms in the NZ fisheries industry. One exhibits a strong ???technological base??? and enjoys a solid foundation for sustainable growth through entrepreneurial management, whereas others appear to have weaker bases and lack entrepreneurial management. The result is the dismal situation described above.

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