428 results for Conference poster

  • In vivo effects of hyperosmotic perilymph perfusion on hair cell and neural potentials

    O'Beirne, G.A.; Patuzzi, R.B. (2008)

    Conference poster
    University of Canterbury Library

    The effect of osmotic bias on cochlear potentials was investigated by perfusion of scala tympani with a modified artificial perilymph. The mean osmolality of the artificial perilymph was increased by around 15% (from 303 ± 6 mOsm/kg H2O to 349 ± 1 mOsm/kg H2O) by addition of sucrose. OHC function was assessed using Boltzmann analysis of the low-frequency CM. Neural thresholds and waveforms were monitored at multiple frequencies, and spontaneous neural noise was monitored via a round-window electrode. The 2-minute perfusions caused a 6 ± 4% increase in the maximal CM amplitude, indicating an increase in OHC basolateral permeability, and an 8 ± 1% increase in MET sensitivity, which may reflect a decrease in OHC axial stiffness. The operating-point shifts recorded were more variable: in healthy animals, the hyperosmotic perfusions caused initial operating point shifts towards scala vestibuli of around 1 – 2 meV that were either followed by a brief undershoot towards scala tympani, or initiated a longer-lasting scala tympani operating point shift. Nonetheless, these operating point shifts were smaller than expected, resulting in a less than ±2 meV deviation from the starting point. Neural thresholds during the perfusion fell (by 20 – 30 dB at 22 kHz), and recovered with a time course consistent with the predicted perilymphatic sucrose concentrations at the corresponding BM place for each frequency. The mechanism of the changes observed with these hyperosmotic perfusions is not known, but its effects were not consistent with a simple movement of the reticular lamina towards scala vestibuli. Other data (Marcon and Patuzzi, in preparation) indicate the CAP threshold shifts during these perfusions are most likely mechanical in origin. The experimental results from the guinea pig are compared with simulated perfusions carried out in a mathematical model of cochlear regulation based on the ionic transport mechanisms and motile properties of the outer hair cells.

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  • OpenSHA implementation of the GCIM approach for ground motion selection

    Bradley, B.A. (2010)

    Conference poster
    University of Canterbury Library

    Ground motion selection is known to be an important step in seismic hazard and risk assessment. There have been numerous procedures proposed for selecting ground motions ranging from somewhat ad-hoc guidelines specified in seismic design codes to more rigorous approaches which have found favour in the research-community, but are not yet applied routinely in earthquake engineering practice. The most common method (often specified in seismic design codes) for selecting ground motion records for use in seismic response analysis is based on their "fit" to a Uniform Hazard Spectrum (UHS). This is despite the fact that many studies have highlighted the differences between the UHS and individual earthquake scenarios, and therefore its inappropriateness for use in ground motion selection. The reluctance of the earthquake engineering profession to depart from UHS-based selection of ground motions is arguably because of its simplicity to implement relative to methodologies with sounder theoretical bases. To this end, the aim of the present work was to implement a recently developed Generalised Conditional Intensity Measure (GCIM) approach for ground motion selection (Bradley, 2010) into the open-source seismic hazard analysis software OpenSHA (Field et al. 2003).

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  • Treatment of earthquake-related posttraumatic symptoms with virtual reality

    Dünser, A.; Carter, J.; Dorahy, M.; Britt, E. (2012)

    Conference poster
    University of Canterbury Library

    After major earthquakes, many people suffer from posttraumatic symptoms (PTS) as well as anxiety and distress about ongoing aftershocks. Traditional treatments such as in vivo or imaginal exposure may be of limited applicability for earthquake-related symptoms while others such as cognitive behavioural therapy may not be short enough to deal with the many people needing rapid help after mass disasters. This project aims to examine how virtual reality exposure therapy (VRET) can help people to reduce PTS and strengthen resilience against traumatic stressors. VRET systems are cost-effective, relatively easy to deploy and enable short, focused interventions.

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  • Tools to support scientists involvement in EPO and science education research

    Brogt, E.; Buxner, S.R.; Matiella Novak, M.A. (2012)

    Conference poster
    University of Canterbury Library

    Like all professionals, scienists spend years becoming an expert in their fields of research, but not necessarily at teaching or presenting their work to non-­‐specialist audiences. However, they are often called on to give classroom talks, teach courses, and interact at public events. In addition, many grant funding agencies now require an education and public outreach component to bring the results of front-­line science to the general public in a meaningful way. In addition, evidence of effectiveness as an teacher and thoughtful reflection on educational practice are standard requirements in promotion and tenure applications. In the highly competitive environment of academia, serious engagement with education can thus give a researcher a leg up in his or her research practice and career, beyond the obvious benefits to teaching, university and professional service such engagement may have. A particularly powerful way to create EPO and science education research is by close collaboration between scientists, educators and EPO specialists. Such a collaboration can lead to very high quality EPO and (educational) research outputs, reaching a broader and more diverse audience than they could have reached individually and can help inform practice across all settings, lead to stronger proposals, and strengthen education research studies.

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  • A 3D seismic velocity model for Canterbury, New Zealand for broadband ground motion simulation

    Lee, R.L.; Bradley, B.A.; Pettinga, J.R.; Hughes, M.; Graves, R.W. (2013)

    Conference poster
    University of Canterbury Library

    his poster presents the ongoing development of a 3D Canterbury seismic velocity model which will be used in physics-based hybrid broadband ground motion simulation of the 2010-2011 Canterbury earthquakes. Velocity models must sufficiently represent critical aspects of the crustal structure over multiple length scales which will influence the results of the simulations. As a result, numerous sources of data are utilized in order to provide adequate resolution where necessary. Figure 2: (a) Seismic reflection line showing P-wave velocities and significant geologic horizons (Barnes et al. 2011), and (b) Shear wave profiles at 10 locations (Stokoe et al. 2013). Figure 4: Cross sections of the current version of the Canterbury velocity model to depths of 10km as shown in Figure 1: (a) at a constant latitude value of -43.6˚, and (b) at a constant longitude value of 172.64˚. 3. Ground Surface and Geologic Horizon Models Figure 3: (a) Ground surface model derived from numerous available digital elevation models, and (b) Base of the Quaternary sediments derived from structural contours and seismic reflection line elevations. The Canterbury region has a unique and complex geology which likely has a significant impact on strong ground motions, in particular the deep and loose deposits of the Canterbury basin. The Canterbury basin has several implications on seismic wave phenomena such as long period ground motion amplification and wave guide effects. Using a realistic 3D seismic velocity model in physics-based ground motion simulation will implicitly account for such effects and the resultant simulated ground motions can be studied to gain a fundamental understanding of the salient ground motion phenomena which occurred during the Canterbury earthquakes, and the potential for repeat occurrences in the Canterbury region. Figure 1 shows the current model domain as a rectangular area between Lat=[-43.2˚,-44.0˚], and Lon=[171.5˚,173.0˚]. This essentially spans the area between the foot of the Southern Alps in the North West to Banks Peninsula in the East. Currently the model extends to a depth of 50km below sea level.

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  • Digitising a Bibliography of Writing by Maori in English

    Thomson, C.J. (2012)

    Conference poster
    University of Canterbury Library

    The attempt to produce a bibliography of all writng by Māori in the English language over a period of more than a hundred years is an incredibly ambitious task. Bridget Underhill’s 1998 doctoral thesis achieves nothing less, seeking to collect and annotate writing by Māori in English from the earliest documents to the time of compilation, which terminated in September 1998. It includes Māori writers in English, Māori translators of Māori texts, largely occurring in the period before 1870, and Māori writers transcribing, translating or in the original. Texts represented include fiction, prose, drama, nonfiction, medical reports, geographical accounts and oral accounts. The bibliography attempts to represent writing from all iwi of Aotearoa

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  • QuakeCoRE Ground Motion Simulation Computational Workflow

    Bae, Sung Eun; Polak, Viktor; Clare, Richard; Bradley, Brendon; Razakindrakoto, Hoby (2016)

    Conference poster
    University of Canterbury Library

    Significant portions of QuakeCoRE research require large-scale computationally-intensive numerical ground motion (GM) simulations. The amount of data and complexity of computation make the large-scale simulation practically impossible to run on a researcher’s workstation. QuakeCoRE started collaboration with New Zealand eScience Infrastructure(NeSI), the national high performance computing (HPC) provider to gain the necessary computational capacity and execution speed.

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  • Documenting natural hazard risk communication needs, challenges and innovations through participatory engagement

    Dohaney, Jacqueline; Wilson, Thomas; Bradley, Brendon; Brogt, Erik; Kennedy, Ben; Hudson-Doyle, Emma; Johnston, David (2016)

    Conference poster
    University of Canterbury Library

    Engineers often receive limited or no formal training in risk communication and may not have time to be up to date with current communication research. Additionally, communication training of practitioners is often 1-dimensional and recipe-style, and doesn’t explore contextual and situational nature of communication. Over the past couple of years, we have developed innovative curricula to teach risk and crisis communication to upper year geoscience, emergency management and engineering students at the University of Canterbury and affiliated institutions in New Zealand. This research involved measuring students’ communication performances and building a new model for understanding how communication is learned, resulting in statistically significant improvements of students’ perceptions and confidence. There is considerable experience and innovation within the New Zealand natural hazard risk communication community, so we aim to integrate this knowledge with our research as a ‘value add’ project (funded by EQC and QuakeCoRE), in which we will work with practitioners to create joint recommendations for improving risk and crisis communication, for the benefit of the wider community. In this poster, we will share the ‘lessons learned’ from our communication training experiences, and why they are important for teaching scientists and engineers how to communicate. Additionally, we will highlight some preliminary findings from engaging with professionals and ask the QuakeCoRE community to consider working with us on this important initiative. Lastly, we will highlight the successes and failures of running our knowledge transfer initiative, which is useful for professionals and organisations hoping to improve communication skills in engineering and the sciences.

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  • Sensitivity of predicted liquefaction-induced lateral displacements from the 2010 Darfield and 2011 Christchurch earthquakes

    Robinson, K.; Cubrinovski, M.; Bradley, B.A. (2013)

    Conference poster
    University of Canterbury Library

    Liquefaction-induced lateral spreading in Christchurch and surrounding suburbs during the recent Canterbury Earthquake Sequence (2010-2011) caused significant damage to structures and lifelines located in close proximity to streams and rivers. Simplified methods used in current engineering practice for predicting lateral ground displacements exhibit a high degree of epistemic uncertainty, but provide ‘order of magnitude’ estimates to appraise the hazard. We wish to compare model predictions to field measurements in order to assess the model’s capabilities and limitations with respect to Christchurch conditions. The analysis presented focuses on the widely-used empirical model of Youd et al. (2002), developed based on multi-linear regression (MLR) of case history data from lateral spreading occurrence in Japan and the US. Two issues arising from the application of this model to Christchurch were considered: • Small data set of Standard Penetration Test (SPT) and soil gradation indices (fines content FC, and mean grain size, D50) required for input. We attempt to use widely available CPT data with site specific correlations to FC and D50. • Uncertainty associated with the model input parameters and their influence on predicted displacements. This has been investigated for a specific location through a sensitivity analysis.

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  • A comparison of ground motions and first-hand experience of the 2011 Mw6.3 Christchurch, New Zealand and 2011 Mw9.0 Tohoku, Japan earthquakes

    Bradley, B.A. (2013)

    Conference poster
    University of Canterbury Library

    This poster provides a comparison between the strong ground motions observed in the 22 February 2011 Mw6.3 Christchurch earthquake with those observed in Tokyo during the 11 March 2011 Mw9.0 Tohoku earthquake. The destuction resulting from both of these events has been well documented, although tsunami was the principal cause of damage in the latter event, and less attention has been devoted to the impact of earthquake-induced ground motions. Despite Tokyo being located over 100km from the nearest part of the causative rupture, the ground motions observed from the Tohoku earthquake were significant enough to cause structural damage and also significant liquefaction to loose reclaimed soils in Tokyo Bay. The author was fortunate enough (from the perspective of an earthquake engineer) to experience first-hand both of these events. Following the Tohoku event, the athor conducted various ground motion analyses and reconniassance of the Urayasu region in Tokyo Bay affected by liquefaction in collaboration with Prof. Kenji Ishihara. This conference is therefore a fitting opportunity in which to discuss some of authors insights obtained as a result of this first hand knowledge. Figure 1 illustrates the ground motions recorded in the Christchurch CBD in the 22 February 2011 and 4 September 2010 earthquakes, with that recorded in Tokyo Bay in the 11 March 2011 Tohoku earthquake. It is evident that these three ground motions vary widely in their amplitude and duration. The CBGS ground motion from the 22 February 2011 event has a very large amplitude (nearly 0.6g) and short duration (approx. 10s of intense shaking), as a result of the causal Mw6.3 rupture at short distance (Rrup=4km). The CBGS ground motion from the 4 September 2010 earthquake has a longer duration (approx. 30s of intense shaking), but reduced acceleration amplitude, as a result of the causal Mw7.1 rupture at a short-to-moderate distance (Rrup=14km). Finally, the Urayasu ground motion in Tokyo bay during the 11 March 2011 Tohoku earthquake exhibits an acceleration amplitude similar to the 4 September 2010 CBGS ground motion, but a significantly larger duration (approx 150s of intense shaking). Clearly, these three different ground motions will affect structures and soils in different ways depending on the vibration characteristics of the structures/soil, and the potential for strength and stiffness degradation due to cumulative effects. Figure 2 provides a comparison between the arias intensities of the several ground motion records from the three different events. It can be seen that the arias intensities of the ground motions in the Christchurch CBD from the 22 February 2011 earthquake (which is on average AI=2.5m/s) is approximately twice that from the 4 September 2010 earthquake (average AI≈1.25). This is consistent with a factor of approximately 1.6 obtained by Cubrinovski et al. (2011) using the stress-based (i.e.PGA-MSF) approach of liquefaction triggering. It can also be seen that the arias intensity of the ground motions recorded in Tokyo during the 2011 Tohoku earthquake are larger than ground motions in the Christchurch CBD from the 4 September 2011 earthquake, but smaller than those of the 22 February 2011 earthquake. Based on the arias intensity liquefaction triggering approach it can therefore be concluded that the ground motion severity, in terms of liquefaction potential, for the Tokyo ground motions is between those ground motions in Christchurch CBD from the 4 September 2010 and 22 February 2011 events.

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  • Enhancement of MRC Modelling Tools in the 3S Basin to Improve Transboundary River Basin Management

    Piman, T.; Cochrane, T.A. (2012)

    Conference poster
    University of Canterbury Library

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  • Hubble expansion variance and the cosmic rest frame

    Wiltshire, D.L.; Smale, P.R, Mattsson, T.; Watkins, R.; Nazer, M.A.; Bolejko, K.; McKay, J.H. (2014)

    Conference poster
    University of Canterbury Library

    Average homogeneity is only reached on scales greater than 70{100h?1Mpc yet standard peculiar velocity approaches assume an most Euclidean geometry below this scale. Furthermore, the Friedmann equation is applied in the nonlinear regime, although this has no motivation in the fundamental principles of general relativity. We investigate the variance of the Hubble expansion in a manner which makes no prior geometrical assumptions, other than the existence of a suitably averaged linear Hubble law. We use the COMPOSITE data set of 4534 galaxies [Watkins, Feldman and Hudson (2009)].

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  • Effects of realistic fault geometry on simulated ground motions in the 2010 Darfield Earthquake

    Razakindrakoto, Hoby; Bradley, Brendon; Graves, R.W. (2016)

    Conference poster
    University of Canterbury Library

    Source representation is an essential component of physics-based ground motion simulations. However, its inherent non-uniqueness leads to different representations for the same fault rupture. For the 2010 Darfield earthquake, various source models have been proposed that primarily differ in fault geometry and rupture process.

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  • Seismic hazard analysis and ground motion selection considering directivity effects

    Tarbali, Karim; Bradley, Brendon; Baker, Jack W. (2016)

    Conference poster
    University of Canterbury Library

    Selecting appropriate ground motion ensembles is a key step in assessing the seismic performance of engineered systems through time-domain seismic response analyses. Recent developments in earthquake rupture forecast and ground motion models (GMMs) provide the engineering community with advanced empirical models to consider physical processes such as rupture directivity in seismic hazard calculations. This study presents an example application of such models to assess the seismic hazard in the near-fault region and subsequently select ground motion ensembles that appropriately represent the target hazard. Implications of the variability in the selected ground motion characteristics are discussed in terms of the demand hazard and collapse fragility.

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  • A fast method for psychophysical estimation of nonlinear cochlear processing using Schroeder phase harmonic complexes

    Rahmat, S.B.; O'Beirne, G.A. (2014)

    Conference poster
    University of Canterbury Library

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  • QuakeCoRE and OpenSees (Year 1): Optimisation of Source Code, Pre- and Post-Processing Tools, and Community Development

    McGann, Chris; Jeong, Seokho; Bradley, Brendon; Tarbali, K.; Wotherspoon, Liam; Lagrava, D.; Bae, Sung Eun (2016)

    Conference poster
    University of Canterbury Library

    The OpenSees finite element platform (Open System for Earthquake Engineering Simulation) developed through the University of California Berkeley is the principal collaborative software identified by QuakeCoRE Technology Platform 4 for use in detailed seismic response modelling of individual infrastructure components. OpenSees was selected for this purpose due to its capabilities as an open-source platform for sequential and parallel analysis of both geotechnical and structural systems. OpenSees is one of the few tools available with all of these attributes, and due to this unique combination of features it meets all three of the underlying principles identified for QuakeCoRE Technology Platform 4: it is open-source, it is scalable (able to make use of HPC resources), and it is flexible (works for variety of problem types and able to work with other QuakeCoRE software modules).

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  • Live & Web-based Parcel Monitoring with Low-cost Sensors

    Bröring, A.; Delikostidis, I.; Fries, K.; Heitmann, S.; Koalick, S.; Krüger, T. (2013)

    Conference poster
    University of Canterbury Library

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  • Canterbury Water Management Strategy

    Jenkins, B.; Friend, J.; Midgley, G. (2014)

    Conference poster
    University of Canterbury Library

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  • Shallow shear wave velocity characterization of the urban Christchurch, New Zealand region

    McGann, C.R.; Bradley, B.A.; Cubrinovski, M. (2014)

    Conference poster
    University of Canterbury Library

    This poster provides a summary of the development of a 3D shallow (z 15,000 logs as of 01/01/2014). In particular, the 3D model provides shear wave velocities for the surficial Springston Formation, Christchurch Formation, and Riccarton gravel layers which generally comprise the upper 40m in the Christchurch urban area. Point-estimates are provided on a 200m-by- 200m grid from which interpolation to other locations can be performed. This model has applications for future site characterization and numerical modeling efforts via maps of timeaveraged Vs over specific depths (e.g. Vs30, Vs10) and via the identification of typical Vs profiles for different regions and soil behaviour types within Christchurch. In addition, the Vs model can be used to constrain the near-surface velocities for the 3D seismic velocity model of the Canterbury basin (Lee et al. 2014) currently being developed for the purpose of broadband ground motion simulation.

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  • Low frequency (f=1Hz) ground motion simulations of 10 events in the 2010-2011 Canterbury earthquake sequence

    Bradley, B.A.; Graves, R.W. (2014)

    Conference poster
    University of Canterbury Library

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