Senior Recital:Chris Griffith, Double Bass

Kemp Recital Hall Saturday Evening March 1, 2008 6:00p.m

Dynamic tipping in the non-smooth Stommel-box model, with fast oscillatory forcing

We study the behavior at tipping points close to non-smooth fold bifurcations in non-autonomous systems. The focus is the Stommel-Box, and related climate models, which are piecewise-smooth continuous dynamical systems, modeling thermohaline circulation. We obtain explicit asymptotic expressions for the behavior at tipping points in the settings of both slowly varying freshwater forcing and rapidly oscillatory fluctuations. The results, based on combined multiple scale and local analyses, provide conditions for the sudden transitions between temperature-dominated and salinity-dominated states. In the context of high frequency oscillations, a multiple scale averaging approach can be used instead of the usual geometric approach normally required for piecewise-smooth continuous systems. The explicit parametric dependencies of advances and lags in the tipping show a competition between dynamic features of the model. We make a contrast between the behavior of tipping points close to both smooth Saddle–Node Bifurcations and the non-smooth systems studied on this paper. In particular we show that the non-smooth case has earlier and more abrupt transitions. This result has clear implications for the design of early warning signals for tipping in the case of the non-smooth dynamical systems which often arise in climate models.</p

The importance of scale in spatially varying coefficient modeling

While spatially varying coefficient (SVC) models have attracted considerable attention in applied science, they have been criticized as being unstable. The objective of this study is to show that capturing the "spatial scale" of each data relationship is crucially important to make SVC modeling more stable, and in doing so, adds flexibility. Here, the analytical properties of six SVC models are summarized in terms of their characterization of scale. Models are examined through a series of Monte Carlo simulation experiments to assess the extent to which spatial scale influences model stability and the accuracy of their SVC estimates. The following models are studied: (i) geographically weighted regression (GWR) with a fixed distance or (ii) an adaptive distance bandwidth (GWRa), (iii) flexible bandwidth GWR (FB-GWR) with fixed distance or (iv) adaptive distance bandwidths (FB-GWRa), (v) eigenvector spatial filtering (ESF), and (vi) random effects ESF (RE-ESF). Results reveal that the SVC models designed to capture scale dependencies in local relationships (FB-GWR, FB-GWRa and RE-ESF) most accurately estimate the simulated SVCs, where RE-ESF is the most computationally efficient. Conversely GWR and ESF, where SVC estimates are naively assumed to operate at the same spatial scale for each relationship, perform poorly. Results also confirm that the adaptive bandwidth GWR models (GWRa and FB-GWRa) are superior to their fixed bandwidth counterparts (GWR and FB-GWR)

Bioportal: Ontologies and integrated data resources at the click of the mouse

BioPortal is a Web portal that provides access to a library of biomedical ontologies and terminologies developed in OWL, RDF(S), OBO format, Protégé frames, and Rich Release Format. BioPortal functionality, driven by a service-oriented architecture, includes the ability to browse, search and visualize ontologies (Figure 1). The Web interface also facilitates community-based participation in the evaluation and evolution of ontology content

Commercial Space Tracking Services for Small Satellites

LeoLabs demonstrates that small satellites, including 1U CubeSats and smaller, are well-tracked to high accuracy by its worldwide network of phased array radars. With its network of two operations radars (valid as of June 2019), LeoLabs is able to provide high-precision ephemeris services for 1U and sub-1U satellites. Roughly 95% of the time, tracking is maintained to better than 1 km at time of estimation (these uncertainties grow when propagating the states). Approximately 50% of the time, these state estimates are better than 200 meters. The quality of the fitted orbits will improve as new LeoLabs radar sites are brought online. Precision tracking services are provided by LeoLabs as a commercial service to small spacecraft operators. Such services are also valuable for regulatory purposes (where detectability and trackability are concerns), for providing backup tracking should GPS not be available, and for safety enhancements by having smaller covariances in instances of potential conjunctions with other satellites

Planar torsion spring

A torsion spring comprises an inner mounting segment. An outer mounting segment is located concentrically around the inner mounting segment. A plurality of splines extends from the inner mounting segment to the outer mounting segment. At least a portion of each spline extends generally annularly around the inner mounting segment

Does an incremental approach to implementing programmatic assessment work? Reflections on the change process

In 2017, the School of Medicine (Fremantle) of the University of Notre Dame Australia began moving towards programmatic assessment. Programmatic assessment seeks to achieve robust assessment validity through the assessment of a large number of low-stakes activities or data points. These data points exemplify assessment as learning by valuing feedback, discussion and reflection, ultimately leading to deeper student engagement without compromising credible decision-making on student progress. The School adopted an incremental approach to implementing programmatic assessment that included first establishing data-informed mentoring, and then activating a continuous assessment program that contributed simultaneously to student learning and School decision-making. Action research helped understand the impact of the initiative. Re-engineering continuous assessment as an incremental step towards programmatic assessment proved to be problematic. Some ideas are proposed to draw the strands of programmatic assessment together that may be useful for others to chart a more fruitful path

Can training improve staff skills with complex trauma?

Purpose: Studies show that experiences of repeated or complex trauma are very common in patients with severe mental health problems. Unfortunately, many professionals do not routinely ask about abuse, due to concerns about how to ask and respond. There is also a need for frontline staff to be trained in trauma-informed care. The purpose of this paper is to identify the needs of inpatient staff and developed a tailor-made training package. Design/methodology/approach: A training programme was developed from focus-group discussion and delivered to the team. Questionnaires were administered pre-, post-training and at three-month follow-up, to assess changes in knowledge, confidence and worries in the assessment and treatment of complex trauma. Findings: There was an increase in self-reported staff confidence (p=0.001) and knowledge (p=0.028) about working with complex trauma and their worries decreased (p=0.026) between pre- and post-training. Practical implications: In order to sustain the benefits of training for longer, recommendations were made to the service for on-going training, supervision and evaluation. Originality/value: Given the recent interest in complex trauma within the literature (Diagnostic and Statistical Manual of Mental Disorders – Fifth Version (DSM-V); International Statistical Classification of Diseases – 11th Version (ICD-11)), the piloting and development of complex trauma training packages is timely. To the author’s knowledge, this is the first published account of complex trauma training for inpatient staff. This paper offers clinical and research implications to services who may want to develop as trauma-informed services within the NHS.</p