5,251 results for 2014

  • Advanced dual composition control for high-purity multi-component distillation column

    Udugama, IA; Munir, TM; Kirkpatrick, Robert; Young, Brent; Yu, Wei (2014)

    Conference item
    The University of Auckland Library

    The control of industrial dual high-purity methanol distillation columns is complicated since there are non-linearities involved. Due to economic factors, these distillation columns have strict product ethanol specification (less than 10 ppm), and require a high level of product recovery. Because of environmental factors the bottoms flow cannot contain more than 5 ppm of methanol for a prolonged period. Industrial methanol producers achieve this target by over refluxing the distillation column which creates a plant bottleneck. In this work, a control scheme was proposed to control a real life industrial dual high-purity methanol distillation column without exceeding specifications set by a commercial methanol producer with minimal reflux ratio. The control scheme keeps the product specification at the top by controlling the product flow, while an ethanol profile composition analyser located nearby the side draw is used to control the reboiler duty. The simulation results show that the proposed method can provide a reliable set-point track performance.

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  • Effect of catalyst performance on high purity industrial methanol distillation

    Udugama, IA; Roberts, A; Kirkpatrick, Robert; Yu, Wei; Young, Brent (2014)

    Conference item
    The University of Auckland Library

    The industrial synthesis of crude methanol from natural gas has improved a great deal in past decades due to improvements in catalyst performance. This has significantly reduced the ethanol in distillation feed from 600 ppm to 150 ppm, making the separation much easier. However most plants in operation today date back decades and some operate the distillation columns under outdated operating ideologies. This paper uses a reliable multicomponent high purity distillation model built using commercial simulator software to investigate the effect of improvements in catalyst performance on distillation. This information is then used to determine optimal recovery and throughput operating conditions for different economic situations.

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  • A texture-processing model of the 'visual sense of number'

    Morgan, M; Raphael, S; Tibber, M; Dakin, Steven (2014-09-07)

    Journal article
    The University of Auckland Library

    It has been suggested that numerosity is an elementary quality of perception, similar to colour. If so (and despite considerable investigation), its mechanism remains unknown. Here, we show that observers require on average a massive difference of approximately 40% to detect a change in the number of objects that vary irrelevantly in blur, contrast and spatial separation, and that some naive observers require even more than this. We suggest that relative numerosity is a type of texture discrimination and that a simple model computing the contrast energy at fine spatial scales in the image can perform at least as well as human observers. Like some human observers, this mechanism finds it harder to discriminate relative numerosity in two patterns with different degrees of blur, but it still outpaces the human. We propose energy discrimination as a benchmark model against which more complex models and new data can be tested.

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  • Ontogeny and control of the heart rate power spectrum in the last third of gestation in fetal sheep

    Koome, ME; Bennet, Laura; Booth, LC; Davidson, Joanne; Wassink, Guido; Gunn, Alistair (2014-01)

    Journal article
    The University of Auckland Library

    Power spectral analysis of fetal heart rate variability has been proposed to provide a non-invasive estimate of autonomic balance. However, there are few systematic data before birth. We therefore examined developmental changes in the frequency power spectrum at very low (0-0.04 Hz), low (0.04-0.15 Hz) and high (0.15-0.4 Hz) frequencies, and the ratio of low- to high-frequency power (LF/HF) in chronically catheterised, healthy fetal sheep at 0.6 (n = 8), 0.7 (n = 7) and 0.8 gestation age (ga, n = 11). In a second study, 0.8 ga fetuses received either atropine (4.8 mg bolus, then 4.8 mg/h for 30 minutes, n = 6) or 6-hydroxydopamine (6-OHDA, 20 mg/ml at 2.5 ml/h for 3 h, n = 9). Data were analysed by sleep state defined by low voltage-high frequency (LV) or high voltage-low frequency (HV) EEG. Total spectral power increased with gestational age (P < 0.05), while LF/HF decreased from 0.6 to 0.7 ga. At 0.8 ga, heart rate and LF/HF were significantly higher during HV than LV sleep (P < 0.05). Consistent with this, although total spectral power was not significantly greater during HV sleep, there was a significant interaction between sleep state and frequency band (P = 0.02). Both atropine (P = 0.05) and 6-OHDA (P < 0.05) were associated with an overall reduction in spectral power but no significant effect on the LF/HF ratio. This study does not support substantial, consistent differences between the frequencies of sympathetic and parasympathetic activity in late gestation fetal sheep.

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  • Parallel scheduling of task trees with limited memory

    Eyraud-Dubois, L; Marchal, L; Sinnen, Oliver; Vivien, F (2014-10-01)

    Report
    The University of Auckland Library

    This paper investigates the execution of tree-shaped task graphs using multiple processors. Each edge of such a tree represents some large data. A task can only be executed if all input and output data fit into memory, and a data can only be removed from memory after the completion of the task that uses it as an input data. Such trees arise, for instance, in the multifrontal method of sparse matrix factorization. The peak memory needed for the processing of the entire tree depends on the execution order of the tasks. With one processor the objective of the tree traversal is to minimize the required memory. This problem was well studied and optimal polynomial algorithms were proposed. Here, we extend the problem by considering multiple processors, which is of obvious interest in the application area of matrix factorization. With multiple processors comes the additional objective to minimize the time needed to traverse the tree, i.e., to minimize the makespan. Not surprisingly, this problem proves to be much harder than the sequential one. We study the computational complexity of this problem and provide inapproximability results even for unit weight trees. We design a series of practical heuristics achieving different trade-offs between the minimization of peak memory usage and makespan. Some of these heuristics are able to process a tree while keeping the memory usage under a given memory limit. The different heuristics are evaluated in an extensive experimental evaluation using realistic trees.

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  • Electrical circuit creation on Android

    Xu, DD; Hy, M; Kalra, S; Yan, D; Giacaman, Nasser; Sinnen, Oliver (2014)

    Conference item
    The University of Auckland Library

    Most modern circuit design applications use a drag-and-drop approach to circuit creation. This can be both slow and unintuitive. This paper presents Voltique Designer, an Android-based circuit creation tool. The app seeks to combine the benefit of electronic circuit creation with the ease of hand drawing. Using RATA.SSR, Voltique Designer can recognize hand-drawn circuit components. The app analyses the circuit on the fly with a localized version of NGSPICE. User testing shows that Voltique Designer is quick to learn and easy to use compared to existing applications. An electronic logbook app called Montique is developed in conjunction with Voltique Designer.

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  • A new investigative approach to understanding fluid flow migration pathways within the shallow subsurface at Orakei Korako, New Zealand

    Lynne, Bridget; Smith, GJ (2014)

    Conference item
    The University of Auckland Library

    Sinter analyses, infrared imaging, downhole temperature measurements and Ground Penetrating Radar (GPR), were undertaken in 2012 at Orakei Korako, Taupo Volcanic Zone, New Zealand to investigate the inter-relationship of chemistry, temperature and texture of sinters at shallow subsurface depths (90??C. Infrared imaging of individual sites within the geothermal area provided further information on surface temperatures at Orakei Korako. This new multi-method approach identified: (i) areas of heat in the subsurface where there is no present-day evidence of heat in the shallow surface, and (ii) areas of sustained heat in the subsurface as evidenced by the high level of acidic steam condensate overprinting of surface sinter deposits. Repeated surveys will identify if the surface and shallow subsurface conditions mapped in 2012 are changing and map areas of the field that are heating up or cooling down with time.

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  • Paul Auster's writing machine: A thing to write with

    Trofimova, Evija (2014)

    Book
    The University of Auckland Library

    Paul Auster is one of the most acclaimed figures in American literature. Known primarily as a novelist, Auster's films and various collaborations are now gaining more recognition. Evija Trofimova offers a radically different approach to the author's wider body of work, unpacking the fascinating web of relationships between his texts and presenting Auster's canon as a rhizomatic facto-fictional network produced by a set of writing tools. Exploring Auster's literal and figurative use of these tools ??? the typewriter, the cigarette, the doppelg??nger figure, the city ??? Evija Trofimova discovers Auster's ???writing machine???, a device that works both as a means to write and as a construct that manifests the emblematic writer-figure. This is a book about assembling texts and textual networks, the writing machines that produce them, and the ways such machines invest them with meaning. Embarking on a scholarly quest that takes her from between the lines of Auster's work to between the streets of his beloved New York and finally to the man himself, Paul Auster's Writing Machine becomes not just a critical investigation but a critical collaboration, raising important questions about the ultimate meaning of Auster's work, and about the relationship between texts, their authors, their readers and their critics.

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  • From Tutoring to Cognitive Rehabilitation: Exploiting CBM to Support Memory Training

    MITROVIC, Antonija; MATHEWS, Moffat; OHLSSON, Stellan; HOLLAND, Jay; MCKINLAY, Audrey; OGDEN, Scott; BRACEGIRDLE, Anthony; DOPPING-HEPENSTAL, Sam (2014)


    University of Canterbury Library

    Constraint-Based Modeling (CBM) is an effective student modeling approach which has been used successfully in a wide range of instructional domains. Within the Intelligent Computer Tutoring Group (ICTG), we have developed numerous constraint-based tutors and demonstrated their effectiveness in real courses. In this paper, however, we discuss how we use CBM in the area of cognitive rehabilitation after stroke. Our computer-based treatment is aimed at improving prospective memory. Participants are first trained on how to use visual imagery and then practice in a Virtual Reality (VR) environment. We present how we use constraints to track the participant’s progress when performing tasks in the VR environment.

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  • Creating and evaluating a model for a user in a rehabilitative virtual-reality environment

    Ogden, Scott (2014)


    University of Canterbury Library

    The ICTG research group is currently working on a Stroke Rehabilitation virtual reality system to improve prospective memory. In this system there is a need to give the user relevant feedback at the appropriate time. To accomplish this, we must model the user’s progress and understanding. Constraint-based modeling was used to create a user model and provide feedback. One of the main design decisions in implementing this was to decide when constraints should be evaluated. Other important design elements included determining what task the user is attempting. As well as writing the constraints, a constraint editor, scripting language and feedback generator were developed. A case study with a stroke survivor was conducted. This case study was used to further develop constraints. Two domain experts evaluated the validity and timeliness of the feedback and the validity of the fidelity of the user model.

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  • A Virtual Reality Environment for Prospective Memory Training

    Mitrovic, Antonija; Mathews, Moffat; Ohlsson, Stellan; Holland, Jay; McKinlay, Audrey; Ogden, Scott; Bracegirdle, Anthony; Dopping-Hepenstal, Sam (2014)


    University of Canterbury Library

    Prospective Memory (PM), or remembering to perform tasks in the future, is of crucial importance for everyday life. Stroke survivors often have impaired prospective memory, which can interfere with their independent living. In 2011, we started working on computer-based training for improving prospective memory in stroke patients. The primary goal of our project is to develop an effective PM treatment that could be used without the input of clinicians. Our approach combines the use of visual imagery with practice in a Virtual Reality (VR) environment. In this paper, we present the VR environment and the user modelling approach implemented

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  • Community saving and economic empowerment: A case study of the Village Development Bank (VDB) model in Ta Yaek commune, Soutr Nikum district, Siem Reap province, Cambodia

    Men, P; Ngin, C; Heng, N; Rath, C (2014)

    Report
    The University of Auckland Library

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  • Longitudinal analysis of the environmental attitudes of university students

    shephard, Kerry; Harraway, John; Jowett, Tim; Lovelock, Brent; Skeaff, Sheila; Slooten, Liz; Furnari, Mary; Strack, Mick (2014)

    Journal article
    University of Otago

    This article addresses the important questions that higher education institutions ask concerning their impact on their students’ sustainability-related attributes ‘How do our students’ worldviews change as they experience higher education with us?’ The process of monitoring such a dynamic entity is fraught with statistical complexity but may not be impossible for an institution willing to ask whether or not its educational efforts in ‘education for sustainability’, ‘education for sustainable development’ or ‘environmental education’, and campus sustainability developments, are paralleled by changes in the attitudes of its students. We describe here a longitudinal survey process based on the revised New Ecological Paradigm scale, with two cohorts of students, in three programmes of study, operating over four years, with multiple survey inputs by each student. We implemented the longitudinal analysis using a linear mixed-effects model and describe here the development and testing of this model. We conclude that higher education institutions can benchmark the sustainability attributes of their students and monitor changes, if they are minded to. We invite higher education practitioners worldwide to join us in further developing suitable research instruments, processes and statistical models, and in further analysing the assumptions that link higher education to sustainability and to global citizenship.

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  • Is the environmental literacy of university students measurable?

    Shephard, Kerry; Harraway, John; Lovelock, Brent; Skeaff, Sheila; Slooten, Liz; Strack, Mick; Furnari, Mary; Jowett, Tim (2014)

    Journal article
    University of Otago

    We report the development and piloting of an evaluative instrument and process for monitoring the environmental literacy (EL) of undergraduate students in one large research-led university in New Zealand. The instrument addresses knowledge, affect and competencies in the general area of EL in line with this institution’s adoption of EL as a graduate attribute (or in a US context, a general-education learning outcome, and something to be fostered throughout a student’s education). The instrument and associated processes were designed to fit within conventional institutional mechanisms that manage student feedback on the quality of teaching. The instrument was tested with more than 600 students from more than eight programmes over the course of a year and its use stressed that students were anonymous within the survey. We conclude that evaluating (or in a US context, assessing) the extent to which students acquire EL is an achievable objective and is a reasonable expectation for any higher education institution that claims to foster this attribute.

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  • Physico-chemical and environmental controls on siliceous sinter formation at the high-altitude El Tatio geothermal field, Chile

    Nicolau, C; Reich, M; Lynne, Bridget (2014-08-01)

    Journal article
    The University of Auckland Library

    El Tatio geothermal field is located 4270 m above sea level in the Altiplano, northern Chile. Siliceous sinter deposits from El Tatio were studied to understand the influence of water chemistry and the extreme climatic conditions on their textures and mineralogy. The results of this study show that the mineralogy of El Tatio sinters include of opal-A and accessory minerals, such as halite, gypsum and cahnite (Ca4B2As2O12???4H2O), which precipitate by full evaporation of high arsenic, boron and calcium thermal waters. El Tatio sinters show a high degree of structural disorder, probably linked to cation incorporation into the silica structure and/or the occurrence of micro- to nano-scale accessory minerals. The high content of cations in the thermal waters is strongly tied to relatively high silica precipitation rates considering silica concentration in water (147???285 mg/l SiO2). Precipitation rate reach 2.5 kg/m2 per year based on in situ precipitation experiments. The particular environmental conditions of this high-altitude geothermal area that produce high water cooling rate and high evaporation rate, may also be responsible for the fast silica precipitation. Low environmental temperatures create freezing-related sinter textures (i.e., silica platelets and micro columns/ridges). Silicified microbial filaments are also characteristic of El Tatio sinters, and they are indicative of water temperature and hydrodynamic conditions at the moment of sinter formation. However, sinter textural interpretation in a high-altitude Andean context must be done carefully as specific relationships between microbial and hydrodynamic textures are found.

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  • MAPS: Living, moving, emerging assemblages

    Matapo, Jacoba; Roder, Howard (2014-07)

    Journal article
    The University of Auckland Library

    This research narrative tells the story of a M??ori immersion early childhood centre???s engagement with the performing arts. In this research, and fundamental to this narrative is the provocation that came from the drama based Community Artist who, joining the centre, listened, shared, planned and lived drama arts practices with the children and teachers. This activity rests within a more extended arts based teaching and research learning initiative (TRLI) known as Move, Act, Play, Sing (MAPS), which also involved provocations from music and dance Community Artists. Drama and storytelling are the focus of the encounters shared here, particularly what might be understood as a ???walking performance??? linked to a local mountain, which featured in the children???s lives and the life of the centre becoming-M??ori. What emerged throughout the overall project was an affirmation of the intricate ties to lived experiences, sensations, encounters, interactions and intensities that are present in children???s work. Drama as ???real??? or living is supported within the imaginary, where Deleuze identifies ???real??? as both virtual and the actual (1988). Attention is drawn to the movement or leakage between virtual and the actual, enabling another of Deleuze???s concepts to operate, namely, the rhizome (Sellers, 2013). This research also draws on Deleuze and Guattari???s (1988) concept of assemblages of desire invoking the imaginary as a new means of expression affecting unexpected relations and connections, and it is within these emergent, unexpected, yet still anticipated potentials that this article seeks new possibilities for drama in early childhood education.

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  • Robert MacCulloch: Out of control - our red tape tangle

    MacCulloch, Robert (2014-10-29)

    Unclassified
    The University of Auckland Library

    The regulatory state in New Zealand is on the march. The number of regulations made by governments each year from 1985 onward has shot up. The numbers don't include local government regulations because nobody has counted them. Has the rise of the regulatory state added to the well-being of our country? No-one knows, as there has been no serious attempt to measure their costs and benefits.

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  • Step-parenting

    Cartwright, Patricia (2014)

    Book item
    The University of Auckland Library

    Many Australian children spend part of their childhood living in a step-family and many will grow up to be the step-parents of tomorrow. According to the Australian Bureau of Statistics [ABS] (2007), approximately one in ten couple families contain resident stepchildren. In Wave 3 of the Household, Income and Labour Dynamics in Australia (HILDA) survey, 13% of households had either residential or non-residential step-children, or both (Qu & Weston, 2005). Early research, both in Australia and overseas, has found that children often experience difficulty adjusting to the changes associated with their parents??? repartnering, especially in regard to developing a relationship with a parent???s new partner, the step-parent. This chapter focuses on the role of the step-parent and presents an overview of research and clinical literature that informs our understanding of the role and experiences of being or having a step-parent.

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  • The latest international survey of adult skills: What does PIAAC mean for us in New Zealand?

    Coben, Diana; Earle, David (2014)

    Conference item
    University of Waikato

    • What can PIAAC tell us – and what can it not tell us? • What kinds of shifts in adults skills in the population might we expect to see since the ALL Survey reported in 2006? • What might PIAAC mean for adult literacy and numeracy educators, learners and the general public? • What are the implications of PIAAC for educators?

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  • Marine natural products

    Blunt, JW; Copp, Brent; Keyzers, RA; Munro, MHG; Prinsep, MR (2014-01-03)

    Journal article
    The University of Auckland Library

    This review covers the literature published in 2012 for marine natural products, with 1035 citations (673 for the period January to December 2012) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1241 for 2012), together with the relevant biological activities, source organisms and country of origin. Biosynthetic studies, first syntheses, and syntheses that lead to the revision of structures or stereochemistries, have been included. ?? 2014 The Royal Society of Chemistry.

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