106 results for The University of Auckland Library, Conference paper

  • Virtualisation

    Smith, Russell; Chaffe, Tim (2007)

    Conference paper
    The University of Auckland Library

    An open access copy of this article is available and complies with the copyright holder/publisher conditions. In late 2004 the University of Auckland was drowning in servers, parched for storage and had spaghetti for a data center network. Faced with ever growing University demand, the need for disaster recovery and an impending data center move in 2007, something had to give. The infrastructure blinked first. The University embarked on a radical overhaul of its infrastructure virtualising networks, storage and computing platforms. This paper outlines the drivers, the process, the thinking, the technologies and outcome of what has the look and feel of a utility services model; one that we hope will benefit the entire University.

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  • Strategic Alignment – Attempting to Crack the Nut

    Fordyce, Miles (2009)

    Conference paper
    The University of Auckland Library

    EDUCAUSE Australasia 2009, Perth Western Australia. 3‐6 May 2009 http://www.caudit.edu.au/educauseaustralasia09/. Many papers have been written on how to improve the alignment between IT and Business strategies. This paper serves to discuss the topic in perhaps more practical terms, and outlines the approaches The University of Auckland has taken to generate a working model to assess alignment, and more importantly use the output of the model better articulate the IT Portfolio to senior University management.

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  • Aging gracefully? Reviewing and enhancing Information Commons services at the University of Auckland

    Chidlow, Rachel; Mountifield, Hester (2010)

    Conference paper
    The University of Auckland Library

    Conference programme and links to all papers http://www.vala.org.au/vala2010/prog2010.htm The University Library’s Information Commons Group services and facilities have continued to thrive and improve student life and learning since the opening of the Kate Edger Information Commons in April 2003. The IC Group has a strong strategic focus on continuous improvement in areas of management, staff development, operations, space design, technology, resource development and client services. The IC Group collaborates with ITS in offering and improving electronic campus services for students. This paper outlines the “how” and “why” behind changes and improvements in the IC Group. The benefits to staff and students will also be demonstrated. This paper also briefly discusses the reengineering of the original service model to accommodate changes in learning, technology and student needs.

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  • A simulation-based approach to bidding strategies for network resources in competitive wireless networks

    Beltran, Fernando; Roggendorf, Matthias (2006)

    Conference paper
    The University of Auckland Library

    An open access copy of this article is available and complies with the copyright holder/publisher conditions. The original publication is available from the publisher at http:dx/doi.org/10.1007/11780502_5 We introduce a simulation-based approach to the problem that mobile users may face in a multi-provider environment when seeking to satisfy their demand for bandwidth; if they are allowed to satisfy their individual demands by aggregating shares from two or more providers the problem becomes one of resource allocation in a competitive market. We use the Progressive Second-Price auction at each provider, exploring the properties of three bidding strategies. Simulations aim at learning whether the auction converges at each seller when bidders, either make coordinated or non-coordinated decisions among auctions, or complement already secured shares by bidding at other auctions. Aggregate measures of welfare and sellers' revenue are obtained for each simulation run.

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  • An Improved Magnetic Design for Inductively Coupled Power Transfer System Pickups

    Kacprzak, Dariusz; Covic, Grant; Boys, John T. (2005)

    Conference paper
    The University of Auckland Library

    An open access copy of this article is available and complies with the copyright holder/publisher conditions. This paper presents a new approach to the design of inductively coupled power transfer pickups using electromagnetic modeling techniques. As shown, significant improvements in the level of output power are able to be achieved for a given volume of ferrite by considering the field vectors in and around the ferrite and the power coil. The new design approach undertaken using 3-D simulations, is verified experimentally in the laboratory.

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  • Validating ORA-SS data models using Alloy

    Wang, Lin; Dobbie, Gill; Sun, Jing; Groves, Lindsay (2006)

    Conference paper
    The University of Auckland Library

    An open access copy of this article is available and complies with the copyright holder/publisher conditions. Semistructured data is typically represented using XML. However, little semantic information can be captured using XML. Other data models, such as the object relationship attribute data model for semistructured data (ORA-SS), have been introduced to represent more detailed semantic information. Automatic analysis of the data models would enable us to reveal inconsistencies both at the schema and instance levels of the semistructured data. The aim of this paper is to encode the semantics of the ORA-SS data model in the Alloy formal language and automatically validate the semistructured data design using the Alloy analyzer. It enables us to check the consistency of an ORA-SS schema and its instances.

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  • A simulation model for the dynamic allocation of network resources in a competitive wireless scenario

    Beltran, Fernando; Roggendorf, Matthias (2006)

    Conference paper
    The University of Auckland Library

    An open access copy of this article is available and complies with the copyright holder/publisher conditions. Next-generation wireless networks will enable the usage of different network technologies fully transparent to the user. Applications will be able to dynamically adapt to the conditions and technical constraints of the network. This vision requires a dynamic allocation of scarce network resources to different users. This paper presents simulation results from a model of admission control and dynamic resource allocation in wireless networks, in a two-provider, multiple-user scenario. The access allocation and connection procedure is implemented using an efficient (welfare maximizing) incentive mechanism for capacity allocation at both providers.

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  • Reuse of Components in Formal Modeling and Verification of Distributed Control Systems

    Vyatkin, Valeriy; Hanish, Hans-Michael (2005)

    Conference paper
    The University of Auckland Library

    An open access copy of this article is available and complies with the copyright holder/publisher conditions. This paper describes formal modeling and verification of automation systems ftom the system engineering point of view. Reuse of model components is the key issue in order to bring the scientific modeling methodology into engineering practice. The reuse is achieved by the combination of modular modeling of automation systems with object-oriented description of models in UML style. This allows to benefit from advantages of both worlds: efficiently manage highly hierarchical complex models with UML tools and end up with efficiently executable models with distributed states that are compatible also with IEC61499 function block specifications. The approach is supported by the tool framework that is described in the contribution.

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  • A Comparison of Multilevel Solvers for the Cardiac Bidomain Equations

    Austin, Travis; Trew, Mark; Pullan, Andrew (2005)

    Conference paper
    The University of Auckland Library

    An open access copy of this article is available and complies with the copyright holder/publisher conditions. Computing the extracellular potentials in a bidomain cardiac activation model is a computationally significant step in the solution process. Thus, using a fast solver can drastically reduce the overall time of simulation. Solving for the extracellular potentials involves inverting the matrix coming from the elliptic equation describing the extracellular-intracellular potential coupling. Elliptic equations are known to yield matrices that become progressively more ill-conditioned as the spatial resolution is increased. However, optimal multilevel solution methods are known to exist for these equations given enough effort is placed into developing the correct solution components. Two multilevel solvers that automatically perform much of this work are Black Box Multigrid (BOXMG) and Algebraic Multigrid (AMG). In this paper, we compare the performance of BOXMG and AMG as solvers for the elliptic component of the bidomain equations. Our investigation is with respect to simulations of reentry in two-dimensional cardiac tissue.

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  • A Variable Inductor Based Tuning Method for ICPT Pickups

    James, Jason; Boys, John T.; Covic, Grant (2005)

    Conference paper
    The University of Auckland Library

    An open access copy of this article is available and complies with the copyright holder/publisher conditions. A practical dynamic inductor-tuning circuit for a parallel resonant ICPT power pickup operating at 38.4kHz is described. The method controls the current through a tuning inductor by varying the turn on delay of two power switches. This varies the inductor current so that the tank may be maintained at resonance. Supporting mathematical analysis, circuit simulation and prototype measurements are included. Experimental results have verified the system behaviour.

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  • Using CellML in Computational Models of Multiscale Physiology

    Nickerson, David; Hunter, Peter (2005)

    Conference paper
    The University of Auckland Library

    An open access copy of this article is available and complies with the copyright holder/publisher conditions. A computational modeling framework is presented which enables the integration of multiple physics and spatial scales in models of physiological systems. A novel aspect of the framework is the use of CellML to specify all model and simulation specific mathematical equations including cellular models and material constitutive relationships. Models of cardiac electromechanics at cellular, tissue, and organ spatial scales are used to illustrate the developed and implemented framework and other applications are discussed.

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  • A soft decision output convolutional decoder based on the application of neural networks

    Berber, Stevan (2005)

    Conference paper
    The University of Auckland Library

    An open access copy of this article is available and complies with the copyright holder/publisher conditions. The paper investigates BER characteristics of a new algorithm for decoding convolutional codes based on neural networks. The novelty of the algorithm is in its capability to generate soft output estimates of the message bits encoded. It is shown that the defined noise energy function, which is traditionally used for the soft decoding algorithm of convolutional codes, can be related to the well known log likelihood function. The coding gain is calculated using a developed simulator of a coding communication system that uses a systematic 1/2-rate convolutional code.

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  • Internet Applications for Computational Biology, the CMISS Web Browser Extension and and Use in Education

    Stevens, Carey; Blackett, Shane; LeGrice, Ian; Hunter, Peter (2005)

    Conference paper
    The University of Auckland Library

    An open access copy of this article is available and complies with the copyright holder/publisher conditions. The internet is becoming increasingly accessable and new technologies are enabling the delivery of more features to end users. It is therefore increasingly compelling to develop technology to facilitate the delivery of educational content and computational tools via the internet. Here we report on the internet enabling of the CMISS package as a web browser extension, and its use in a custom online teaching application for medical students.

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  • Controlling Inrush Currents in Inductively Coupled Power Systems

    Boys, John T.; Chen, C.I.; Covic, Grant (2005)

    Conference paper
    The University of Auckland Library

    An open access copy of this article is available and complies with the copyright holder/publisher conditions. In an Inductively Coupled Power Transfer (ICPT) system, a multiplicity of (moving) loads take power from an elongated conductive loop (track) excited by a current in the range of 15-125A by magnetic induction at a VLF frequency of between 5-50kHz. In this application, the track performs the same function as a distribution line in a power system. However, frequency deviations cannot be tolerated in ICPT systems and therefore there are difficulties with inrush power surges as loads switch on. In severe cases, the inrush surge may compromise the security of the whole system. This paper proposes a solution to this problem using an ICPT pickup controller with input shaping where the poles that can cause an inrush are not excited. The paper is supported by theoretical analysis and experimental measurements and is applicable across a wide range of ICPT sizes and applications. The solution reduces the inrush effects to 10% of an uncontrolled system.

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  • High Resolution 3D Imaging of Lung Tissue using Structured Light Microscopy

    Kvistedal, Yme; Tawhai, Merryn; Hunter, Peter; Nielsen, Poul (2005)

    Conference paper
    The University of Auckland Library

    An open access copy of this article is available and complies with the copyright holder/publisher conditions. A 3D reconstruction microscope has been built in order to investigate the structural details of the airway tree and the vasculature of mouse lungs. The objective is to create an anatomically correct finite element model of a mouse lung in order to validate results from simulations obtained using an existing model of the human lung. The 3D reconstruction microscope consists of a fully automated scanning stage, a vibratome and a structured light optical microscope. Structured light microscopy is a new approach to optical sectioning of tissue and offers several advantages over confocal microscopy.

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  • A Replicated Comparison of Cross-Company and Within-Company Effort Estimation Models Using the ISBSG Database

    Mendes, Emilia; Lokan, Chris; Harrison, Robert; Triggs, Christopher (2005)

    Conference paper
    The University of Auckland Library

    An open access copy of this article is available and complies with the copyright holder/publisher conditions. Four years ago was the last time the ISBSG database was used to compare the effort prediction accuracy between cross-company and within-company cost models. Since then more than 2,000 projects have been volunteered to this database, which may have changed the trends previously observed. This paper therefore replicates a previous study by investigating how successful a cross-company cost model is: i) to estimate effort for projects that belong to a single company and were not used to build the cross-company model; ii) compared to a within-company cost model. Our within-company data set had data on 184 software projects from a single company and our cross-company data set employed data on 672 software projects. Our results did not corroborate those from the previous study, showing that predictions based on the within-company model were not significantly more accurate than those based on the cross-company model. We analysed the data using forward stepwise regression.

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  • 65 THz beat frequency observed from a scalar modulation instability experiment

    Kruhlak, Robert; Wong, Gordon; Clark, Heather; Leonhardt, Rainer; Harvey, John; Knight, J C; Wadsworth, W J; Russell, P St. J (2005)

    Conference paper
    The University of Auckland Library

    An open access copy of this article is available and complies with the copyright holder/publisher conditions. We have observed an optical modulation with a period of about 15 fs by beating the anti-stokes wave and the pump wave exiting a photonic crystal fibre. These results confirm the coherence of the sidebands generated by scalar modulation instability in the normal dispersion regime. Future experiments will be conducted to measure the beating of the stokes and the anti-stokes waves.

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  • A preliminary study of the effect of surface coating on the initial deposition mechanisms of dairy fouling.

    Ramachandra, S. S.; Wiehe, S.; Hyland, M. M.; Bansal, B. (2005)

    Conference paper
    The University of Auckland Library

    An open access copy of this article is available and complies with the copyright holder/publisher conditions. Modification of heat transfer surfaces to minimize the effects of fouling in the dairy industry is investigated in the current study. Special attention is given to the initial deposition mechanisms, which are believed to determine the fouling and cleaning performance of the surfaces studied. Preliminary results have been obtained for stainless steel and titanium nitride (TiN) surfaces fouled for 3 minutes with whey protein and calcium phosphate. Scanning Electron Microscopy (SEM) images of air-dried, whey protein fouled samples showed both TiN and stainless steel surfaces were covered with a thin layer of deposit, following the topography of the heating surface. X-ray Photoelectron Spectroscopy (XPS) spectra for the TiN surfaces fouled with whey protein showed carbon and oxygen as the main components present. XPS analysis of the stainless steel surfaces is currently underway. Calcium phosphate fouling on stainless steel and TiN surfaces resulted in formation of a crystal matrix on some parts of the surface, while other parts appeared to have no deposition. X-ray microanalysis of these crystals yielded a Ca/P ratio of 1.4. X-ray Diffraction (XRD) analysis is being undertaken to better identify the phases formed. Also in consideration is SEM analysis under cryogenic conditions, and XPS analysis of freeze-dried samples to eliminate changes taking place during air-drying. Future experiments will involve fouling of diamond-like carbon (DLC) surfaces. It is expected that altering the fouling behavior and therefore deposit adhesion, may influence cleaning performance, which will be tested in cleaning runs. At a later stage, similar investigations will be performed using milk solutions to study the combined effect of proteins and minerals.

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  • Interaction of whey protein with modified stainless steel surfaces.

    Premathilaka, S. S.; Hyland, M. M.; Chen, Z. D.; Watkins, L. R.; Bansal, B. (2007)

    Conference paper
    The University of Auckland Library

    An open access copy of this article is available and complies with the copyright holder/publisher conditions. Modified stainless steel surfaces were fouled with whey protein solutions to study the deposition mechanisms and the effects of surface modification. Stainless steel samples were coated with diamond-like carbon (DLC) and titanium nitride (TiN). These surfaces are expected to present different surface chemistries to stainless steel in terms of their functional groups and hydrophobic or hydrophilic nature. Thus, it is expected that foulant-surface interactions will differ for the various fouled surfaces. The substrates were exposed to a flowing whey protein solution in a fouling rig designed to achieve laminar flow. X-ray Photoelectron Spectroscopy (XPS) was used to study the initial protein-surface interactions of samples fouled for 1 minute at 75°C. Ellipsometry was used to study the fouling and cleaning performance of samples fouled at 75°C and 85°C for up to 30 minutes followed by ultrasonic caustic cleaning of selected samples. XPS showed the presence of similar protein functional groups on all fouled surfaces. The bonding mechanisms during fouling of DLC is different to the stainless steel and TiN surfaces. The peptide link played a more active role at the deposit-surface interface for the non-polar DLC surface, while it was less significant for the two polar surfaces. Ellipsometry revealed that for the three surfaces, fouling increased in the order DLC<DLC. Furthermore, the nature of the surface influenced the structure of the deposit after the initial protein layer was formed. It was concluded that the surface chemistry can influence the deposition mechanisms in terms of the orientation of protein functional groups as well as the amount of fouling, the structure of the deposit and hence the deposit removal behaviour.

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  • Modelling the pelvic floor for investigating difficulties during childbirth

    Li, XS; Kruger, JA; Chung, JH; Nash, MP; Nielsen, PMF (2008)

    Conference paper
    The University of Auckland Library

    Research has suggested that athletes involved in high-intensity sports for sustained periods have a higher probability of experiencing prolonged second stage of labour compared to non-athletes. The mechanism responsible for this complication is unknown but may depend on the relative size or tone of the pelvic floor muscles. Prolonged training can result in enlargement and stiffening of these muscles, providing increased resistance as the fetal head descends through the birth canal during a vaginal birth. On the other hand, recent studies have suggested an association between increased muscle bulk in athletes and higher distensibility. This project aims to use mathematical modelling to study the relationship between the size and tone of the pelvic floor muscles and the level of difficulty during childbirth. We obtained sets of magnetic resonance (MR) images of the pelvic floor region for a female athlete and a female non-athlete. Thirteen components of the pelvic floor were segmented and used to generate finite element (FE) models. The fetal head data was obtained by laser scanning a skull replica and a FE model was fitted to these data. We used contact mechanics to simulate the motion of the fetal head moving through the pelvic floor, constructed from the non-athlete data. A maximum stretch ratio of 3.2 was induced in the muscle at the left lateral attachment point to the pubis. We plan to further improve our modelling framework to include active muscle contraction and fetal head rotations in order to address the hypotheses that there is a correlation between the level of difficulty and the size or tone of the pelvic floor muscles.

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