5,588 results for Conference item

  • Additive Manufacturing of High Resolution Embedded Electronic Systems

    Wasley, T; Li, J; Ta, D; Shephard, J; Stringer, Jonathan; Smith, P; Esenturk, E; Connaughton, C; Kay, R (2016)

    Conference item
    The University of Auckland Library

    Additive Manufacturing (AM) processes can facilitate the rapid iterative product development of electronic devices by optimising their design and functionality. This has been achieved by combining two additive manufacturing processes with conventional surface mount assembly to generate high resolution embedded multilayer electronic circuits contained within a 3D printed polymer part. Bottom-up DLP Stereolithography and material dispensing of isotropic conductive adhesives have been interleaved to deposit microscale features on photopolymer substrates. The material dispensing process has demonstrated the high density deposition of conductors attaining track widths of 134μm and produced interconnects suitable for directly attaching bare silicon die straight to the substrate. Interconnects down to a diameter of 149μm at a pitch of 457μm have been realized. In addition, this research developed a novel method for producing high aspect ratio z-axis connections. These were simultaneously printed with the circuit and component interconnects by depositing through-layer pillars with a maximum aspect ratio of 3.81. Finally, a method to accurately embed the packaged circuit layer within the printed part has been employed using bottom-up stereolithography.

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  • Requirements Fixation

    Mohanani, R; Ralph, P; Shreeve, B (2014)

    Conference item
    The University of Auckland Library

    There is a broad consensus that understanding system desiderata (requirements) and design creativity are both important for software engineering success. However, little research has addressed the relationship between design creativity and the way requirements are framed or presented. This paper therefore aims to investigate the possibility that the way desiderata are framed or presented can affect design creativity. Forty two participants took part in a randomized control trial where one group received desiderata framed as “requirements” while the other received desiderata framed as “ideas”. Participants produced design concepts which were judged for originality. Participants who received requirements framing produced significantly less original designs than participants who received ideas framing (Mann-Whitney U=116.5, p=0.004). We conclude that framing desiderata as “requirements” may cause requirements fixation where designers’ preoccupation with satisfying explicit requirements inhibits their creativity.

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  • Southern Hemisphere Influenza and Vaccine Effectiveness Research and Surveillance

    Huang, Qiu Sue; Turner, Nicola; Baker, Michael G; Williamson, Deborah A; Wong, Conroy; Webby, Richard; Widdowson, Marc-Alain (2015-07)

    Conference item
    The University of Auckland Library

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  • Are dairy heifers achieving liveweight targets?

    McNaughton, LR; Lopdell, Thomas (2012-07)

    Conference item
    The University of Auckland Library

    The reproductive performance of the national dairy herd has declined (Harris et al. 2006). Heifer rearing is one of eight "ingredients" for achieving good reproductive performance identified by the InCalf project (Burke et al. 2007). Many New Zealand dairy farmers graze their heifers on a run-off or pay a grazier to grow the heifers, with heifers commonly leaving the dairy farm at weaning, or nine months of age and returning at around 22 months of age.

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  • Exhaled breath analysis using a carbon nanotube-based sensor array for metabolic and cardiovascular applications

    Gladding, P; Tawhai, Merryn; Cater, John; Mackenzie, E; Villas-Boas, Silas; Taylor, M; Palmer, A; Jain, D; Barbera, J (2015)

    Conference item
    The University of Auckland Library

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  • Affordable housing in Auckland, New Zealand

    Palmer, Kenneth (2015-09-01)

    Conference item
    The University of Auckland Library

    The paper assesses the problem of housing affordability in Auckland, New Zealand. Matters considered include the concept of affordability, substantial increases in the cost of housing, reasons for the increases, increasing land supply, overseas investors, the capital gains tax situation, government response, future outcomes.

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  • From theory to practice: Using professional development to start conversations about academic and information literacy

    Dong, Linfan (2016-07-05)

    Conference item
    The University of Auckland Library

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  • High purity, high recovery, multi-component methanol distillation control

    Udugama, IA; Munir, T; Kirkpatrick, R; Young, Brent; Yu, Wei (2015)

    Conference item
    The University of Auckland Library

    High purity distillation is a well-established area of research. In an industrial setting most columns are operated at high recovery rate due to economic factors. However, most research work in this area overlooks high recovery as well as the fact many operations have multi-component feeds. In high-purity (<. 10. ppm) multi-component methanol distillation the columns are typically operated at a recovery of 97.5%. Despite this relatively high value, even a 1% increase in recovery carries a significant financial incentive. In this work a validated model of a methanol distillation column was built in a commercial process simulator and used to study the dynamic behaviour of a real column operating high recovery levels. Based on the analysis the a novel control scheme has been developed and tested for 99.5% recovery: The control scheme extracts flow and composition information from feed, product and side draw streams to dynamically calculate the mass and energy requirements. The information is then used to set reboiler duty, and to manipulate the set points of the decentralized product ethanol composition controller and side draw flow controller. These actions manage the energy requirement, methanol and ethanol mass balances respectively.

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  • Design and Performance of Bridge Cap Beam/Column Joints using Headed Reinforcement and Mechanical Couplers

    Sritharan, S; Ingham, Jason; Priestley, MJN; Seible, F (1999)

    Conference item
    The University of Auckland Library

    The application of headed reinforcement as a replacement for conventional reinforcement was investigated in two projects relating to the seismic design of bridges. In the first project, a test unit composed of a column, cap beam, footing and knee joint was designed entirely with headed reinforcement, and in the second project a test unit representative of a multi-column bridge bent was investigated, having a cap beam design utilizing both headed reinforcement and a mechanical coupler system. In both investigations the use of recently-developed products facilitated simplified detailing, particularly in the cap beam/column joint region, resulting in reduced reinforcement congestion in the joint zone and improved constructability. The design and performance of the test units under simulated seismic loading are presented.

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  • Generalised Nonblocking

    Malik, Robi; Leduc, Ryan (2008)

    Conference item
    University of Waikato

    This paper studies the nonblocking check used in supervisory control of discrete event systems and its limitations. Different examples with different liveness requirements are discussed. It is shown that the standard nonblocking check can be used to specify most requirements of interest, but that it lacks expressive power in a few cases. A generalised nonblocking check is proposed to overcome the weakness, and its relationship to standard nonblocking is explored. Results suggest that generalised nonblocking, while having the same useful properties with respect to synthesis and compositional verification, can provide for more concise problem representations in some cases.

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  • Variable abstraction and approximations in supervisory control synthesis

    Teixeira, Marcelo; Malik, Robi; Cury, José E. R.; de Queiroz, Max. H. (2013)

    Conference item
    University of Waikato

    This paper proposes a method to simplify Extended Finite-state Automata (EFA) in such a way the least restrictive controllable supervisor is preserved. The method is based on variable abstraction, which involves the identification and removal of irrelevant variables from a model. Variable abstraction preserves controllability, and the paper shows how approximations can be used to ascertain least restrictiveness of the synthesis result. The approach has the modelling benefits of Extended Finite-state Automata, leads to optimal control solutions, and reduces the synthesis cost. An example of a manufacturing system illustrates the contributions.

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  • Improving access to large-scale digital libraries through semantic-enhanced search and disambiguation

    Hinze, Annika; Taube-Schock, Craig; Bainbridge, David; Matamua, Rangi; Downie, J. Stephen (2015)

    Conference item
    University of Waikato

    With 13,000,000 volumes comprising 4.5 billion pages of text, it is currently very difficult for scholars to locate relevant sets of documents that are useful in their research from the HathiTrust Digital Libary (HTDL) using traditional lexically-based retrieval techniques. Existing document search tools and document clustering approaches use purely lexical analysis, which cannot address the inherent ambiguity of natural language. A semantic search approach offers the potential to overcome the shortcoming of lexical search, but even if an appropriate network of ontologies could be decided upon it would require a full semantic markup of each document. In this paper, we present a conceptual design and report on the initial implementation of a new framework that affords the benefits of semantic search while minimizing the problems associated with applying existing semantic analysis at scale. Our approach avoids the need for complete semantic document markup using pre-existing ontologies by developing an automatically generated Concept-in-Context (CiC) network seeded by a priori analysis of Wikipedia texts and identification of semantic metadata. Our Capisco system analyzes documents by the semantics and context of their content. The disambiguation of search queries is done interactively, to fully utilize the domain knowledge of the scholar. Our method achieves a form of semantic-enhanced search that simultaneously exploits the proven scale benefits provided by lexical indexing.

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  • The impact of slow steaming on refrigerated exports from New Zealand

    Carson, James K.; Kemp, R.M.; East, A.R.; Cleland, D.J. (2015)

    Conference item
    University of Waikato

    The practice of slow steaming has had a significant impact on New Zealand export industries with increased transit times in some cases causing significant reductions in shelf life once the product has reached the retail stage. The longer transit times also impose the extra cost to exporters of having more inventory tied up in transit. While there is clear evidence to suggest slow steaming has reduced fuel consumption and hence fuel emissions and fuel costs, these savings have not been passed on by the liners to their customers. However, there is no indication that slow-steaming has caused a significant reduction in export earnings for New Zealand (at least up to the middle of 2014). A predicted move to super-slow steaming would put extra strain on the New Zealand meat industry especially, with their lucrative European chilled lamb market under particular threat.

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  • Progger: an efficient, tamper-evident kernel-space logger for cloud data provenance tracking

    Ko, Ryan K.L.; Will, Mark A. (2014)

    Conference item
    University of Waikato

    Cloud data provenance, or "what has happened to my data in the cloud", is a critical data security component which addresses pressing data accountability and data governance issues in cloud computing systems. In this paper, we present Progger (Provenance Logger), a kernel-space logger which potentially empowers all cloud stakeholders to trace their data. Logging from the kernel space empowers security analysts to collect provenance from the lowest possible atomic data actions, and enables several higher-level tools to be built for effective end-to-end tracking of data provenance. Within the last few years, there has been an increasing number of proposed kernel space provenance tools but they faced several critical data security and integrity problems. Some of these prior tools' limitations include (1) the inability to provide log tamper-evidence and prevention of fake/manual entries, (2) accurate and granular timestamp synchronisation across several machines, (3) log space requirements and growth, and (4) the efficient logging of root usage of the system. Progger has resolved all these critical issues, and as such, provides high assurance of data security and data activity audit. With this in mind, the paper will discuss these elements of high-assurance cloud data provenance, describe the design of Progger and its efficiency, and present compelling results which paves the way for Progger being a foundation tool used for data activity tracking across all cloud systems.

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  • Browsing a digital library: A new approach for the New Zealand digital library

    McKay, Dana; Cunningham, Sally Jo (2003)

    Conference item
    University of Waikato

    Browsing is part of the information seeking process, used when information needs are ill-defined or unspecific. Browsing and searching are often interleaved during information seeking to accommodate changing awareness of information needs. Digital Libraries often support full-text search, but are not so helpful in supporting browsing. Described here is a novel browsing system created for the Greenstone software used by the New Zealand Digital Library that supports users in a more natural approach to the information seeking process. © Springer-Verlag Berlin Heidelberg 2003.

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  • Scaling anisotropy of the power in parallel and perpendicular components of the solar wind magnetic field

    Forman, Miriam A.; Wicks, Robert T.; Horbury, Timothy S.; Oughton, Sean (2013)

    Conference item
    University of Waikato

    Power spectra of the components of the magnetic field parallel (Pzz) and perpendicular (Pzz+Pyy) to the local mean magnetic field direction were determined by wavelet methods from Ulysses’ MAG instrument data during eighteen 10-day segments of its first North Polar pass at high latitude at solar minimum in 1995. The power depends on frequency f and the angle θ between the solar wind direction and the local mean field, and with distance from the Sun. This data includes the solar wind whose total power (Pxx + Pyy + Pzz) in magnetic fluctuations we previously reported depends on f and the angle θ nearly as predicted by the GS95 critical balance model of strong incompressible MHD turbulence. Results at much wider range of frequencies during six evenly-spaced 10-day periods are presented here to illustrate the variability and evolution with distance from the Sun. Here we investigate the aniso tropic scaling of Pzz(f,θ) in particular because it is a reduced form of the Poloidal (pseudo-Alfvenic) component of the (incompressible) fluctuations. We also report the much larger Pxx(f,θ)+Pyy(f,θ) which is (mostly) reduced from the Toroidal (Alfvenic, i.e., perpendicular to both B and k) fluctuations, and comprises most of the total power. These different components of the total power evolve and scale differently in the inertial range. We compare these elements of the magnetic power spectral tensor with “critical balance” model predictions.

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  • Compositional synthesis of discrete event systems using synthesis abstraction

    Mohajerani, Sahar; Malik, Robi; Ware, Simon; Fabian, Martin (2011)

    Conference item
    University of Waikato

    This paper proposes a general method to synthesize a least restrictive supervisor for a large discrete event system model, consisting of a large number of arbitrary automata representing the plants and specifications. A new type of abstraction called synthesis abstraction is introduced and three rules are proposed to calculate an abstraction of a given automaton. Furthermore, a compositional algorithm for synthesizing a supervisor for large-scale systems of composed finite-state automata is proposed. In the proposed algorithm, the synchronous composition is computed step by step and intermediate results are simplified according to synthesis abstraction. Then a supervisor for the abstracted system is calculated, which in combination with the original system gives the least restrictive, nonblocking, and controllable behaviour.

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  • Constructing a focused taxonomy from a document collection

    Medelyan, Olena; Manion, Steve; Broekstra, Jeen; Divoli, Anna; Huang, Anna-Lan; Witten, Ian H. (2013)

    Conference item
    University of Waikato

    We describe a new method for constructing custom taxonomies from document collections. It involves identifying relevant concepts and entities in text; linking them to knowledge sources like Wikipedia, DBpedia, Freebase, and any supplied taxonomies from related domains; disambiguating conflicting concept mappings; and selecting semantic relations that best group them hierarchically. An RDF model supports interoperability of these steps, and also provides a flexible way of including existing NLP tools and further knowledge sources. From 2000 news articles we construct a custom taxonomy with 10,000 concepts and 12,700 relations, similar in structure to manually created counterparts. Evaluation by 15 human judges shows the precision to be 89% and 90% for concepts and relations respectively; recall was 75% with respect to a manually generated taxonomy for the same domain.

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  • Reverse greed in energy and transport

    Kingham, S.; Muir, S. (2016)

    Conference item
    University of Canterbury Library

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  • Predicting polycyclic aromatic hydrocarbon concentrations in soil and water samples

    Holmes, Geoffrey; Fletcher, Dale; Reutemann, Peter (2010)

    Conference item
    University of Waikato

    Polycyclic Aromatic Hydrocarbons (PAHs) are compounds found in the environment that can be harmful to humans. They are typically formed due to incomplete combustion and as such remain after burning coal, oil, petrol, diesel, wood, household waste and so forth. Testing laboratories routinely screen soil and water samples taken from potentially contaminated sites for PAHs using Gas Chromatography Mass Spectrometry (GC-MS). A GC-MS device produces a chromatogram which is processed by an analyst to determine the concentrations of PAH compounds of interest. In this paper we investigate the application of data mining techniques to PAH chromatograms in order to provide reliable prediction of compound concentrations. A workflow engine with an easy-to-use graphical user interface is at the heart of processing the data. This engine allows a domain expert to set up workflows that can load the data, preprocess it in parallel in various ways and convert it into data suitable for data mining toolkits. The generated output can then be evaluated using different data mining techniques, to determine the impact of preprocessing steps on the performance of the generated models and for picking the best approach. Encouraging results for predicting PAH compound concentrations, in terms of correlation coefficients and root-mean-squared error are demonstrated.

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