A Differentiable Distance Approximation for Fairer Image Classification

Naively trained AI models can be heavily biased. This can be particularly problematic when the biases involve legally or morally protected attributes such as ethnic background, age or gender. Existing solutions to this problem come at the cost of extra computation, unstable adversarial optimisation or have losses on the feature space structure that are disconnected from fairness measures and only loosely generalise to fairness. In this work we propose a differentiable approximation of the variance of demographics, a metric that can be used to measure the bias, or unfairness, in an AI model. Our approximation can be optimised alongside the regular training objective which eliminates the need for any extra models during training and directly improves the fairness of the regularised models. We demonstrate that our approach improves the fairness of AI models in varied task and dataset scenarios, whilst still maintaining a high level of classification accuracy. Code is available at https://bitbucket.org/nelliottrosa/base_fairness

Content in Simple Signalling Systems

Our understanding of communication and its evolution has advanced significantly through the study of simple models involving interacting senders and receivers of signals. Many theorists have thought that the resources of mathematical information theory are all that are needed to capture the meaning or content that is being communicated in these systems. However, the way theorists routinely talk about the models implicitly draws on a conception of content that is richer than bare informational content, especially in contexts where false content is important. This article shows that this concept can be made precise by defining a notion of functional content that captures the degree to which different states of the world are involved in stabilizing senders’ and receivers’ use of a signal at equilibrium. A series of case studies is used to contrast functional content with informational content, and to illustrate the explanatory role and limitations of this definition of functional content

An open-source, low-cost NMR spectrometer operating in the mT field regime

In recent years, low field and ultra-low field NMR spectrometers have gained interest due to their portability, lower cost, and reduced subject-induced magnetic field inhomogeneities. Here, we describe the design of a low-cost multinuclear NMR spectrometer operating in the ultra-low field regime (ULF), which possesses high spectral resolution and enables arbitrary pulse programming. An inexpensive multifunction input/output (I/O) device is used to handle waveform generation and digitization in the kHz operating range. A home-built radio frequency (RF) mixing circuit is used to down-mix the NMR signals, allowing for the slower sampling rates and lower memory requirements needed to enable minute-long acquisitions using a standard Windows PC. The LabVIEW code, along with a bill of materials for all components used in the spectrometer, is included. As proof of concept, 1H relaxation measurements and the simultaneous detection of 1H with gas phase and dissolved 129Xe frequencies using the described low field NMR spectrometer are demonstrated

Workflow Optimization of World Micro, Inc. Quality Department

Our group member Nick is currently an intern at World Micro, which is an electronic components distributor for companies manufacturing a variety of commercial, aerospace and military products. When electrical components are purchased from the open market, they need to be traced back to the OEM (Original Equipment Manufacturer) or have a series of tests performed to verify that the parts are authentic and work. The current process time for World Micro’s quality testing and inspection is not efficient causing long lead times, extra work hours, and extra expenses in outsourcing services

Longitudinal nuclear spin relaxation of 129Xe in solution and in hollow fiber membranes at low and high magnetic field strengths

PURPOSE: To measure dissolved-phase 129 Xe T1 values at high and low magnetic fields and the field dependence of 129 Xe depolarization by hollow fiber membranes used to infuse hyperpolarized xenon in solution. METHODS: Dissolved-phase T1 measurements were made at 11.7T and 2.1 mT by bubbling xenon in solution and by using a variable delay to allow spins to partially relax back to thermal equilibrium before probing their magnetization. At high field, relaxation values were compared to those obtained by using the small flip angle method. For depolarization studies, we probed the magnetization of the polarized gas diffusing through an exchange membrane module placed at different field strengths. RESULTS: Total loss of polarization was observed for xenon diffusing through hollow fiber membranes at low field, while significant polarization loss (>20%) was observed at magnetic fields up to 2T. Dissolved-phase 129 Xe T1 values were found consistently shorter at 2.1 mT compared to 11.7T. In addition, both O2 and Xe gas concentrations in solution were found to significantly affect dissolved-phase 129 Xe T1 values. CONCLUSION: Dissolved-phase 129 Xe measurements are feasible at low field, but to assess the feasibility of in vivo dissolved-phase imaging and spectroscopy the T1 of xenon in blood will need to be measured. Both O2 and Xe concentrations in solution are found to greatly affect dissolved-phase 129 Xe T1 values and may explain, along with RF miscalibration, the large discrepancy in previously reported results

Background-Free Detection of Spin-Exchange Dynamics at Ultra-Low Magnetic Field

Ultra-low field nuclear magnetic resonance spectroscopy (NMR) and imaging (MRI) inherently suffer from a low signal-to-noise ratio due to the small thermal polarization of nuclear spins. Transfer of polarization from a pre-polarized spin system to a thermally polarized spin system via the Spin Polarization Induced Nuclear Overhauser Effect (SPINOE) could potentially be used to overcome this limitation. SPINOE is particularly advantageous at ultra-low magnetic field, where the transferred polarization can be several orders of magnitude higher than thermal polarization. Here we demonstrate direct detection of polarization transfer from highly polarized 129 Xe gas spins to 1 H spins in solution via SPINOE. At ultra-low field, where thermal nuclear spin polarization is close to background noise levels and where different nuclei can be simultaneously detected in a single spectrum, the dynamics of the polarization transfer can be observed in real time. We show that by simply bubbling hyperpolarized 129 Xe into solution, we can enhance 1 H polarization levels by a factor of up to 151-fold. While our protocol leads to lower enhancements than those previously reported under extreme Xe gas pressures, the methodology is easily repeatable and allows for on-demand enhanced spectroscopy. SPINOE at ultra-low magnetic field could also be employed to study 129 Xe interactions in solutions

Evaluating the Guideline Enhancement Tool (GET): an innovative clinical training tool to enhance the use of hypertension guidelines in general practice

Background: This project aims to evaluate the effectiveness of an innovative educational intervention in enhancing clinical decision making related to the management of hypertension in general practice. The relatively low level of uptake of clinical practice guidelines by clinicians is widely recognised as a problem that impacts on clinical outcomes. This project addresses this problem with a focus on hypertension guidelines. Hypertension is the most frequently managed problem in general practice but evidence suggests that management of Hypertension in general practice is sub-optimal. Methods/design: This study will explore the effectiveness of an educational intervention named the ‘Guideline Enhancement Tool (GET)’. The intervention is designed to guide clinicians through a systematic process of considering key decision points related to the management of hypertension and provides a mechanism for clinicians to engage with the hypertension clinical guidelines. The intervention will be administered within the Australian General Practice Training program, via one of the regional training providers. Two cohorts of trainees will participate as the intervention and delayed intervention groups. This process is expected to improve clinicians’ engagement with the hypertension guidelines in particular, and enhance their clinical reasoning abilities in general. The effectiveness of the intervention in improving clinical reasoning will be evaluated using the ‘Script Concordance Test’. Discussion: The study design presented in this protocol aims to achieve two major outcomes. Firstly, the trial and evaluation of the educational intervention can lead to the development of a validated clinical education strategy that can be used in GP training to enhance the decision-making processes related to the management of hypertension. This has the potential to be adapted to other clinical conditions and training programs and can benefit clinicians in their clinical decision-making. Secondly, the study explores features that influence the effective use of clinical practice guidelines. The study thus addresses a significant problem in clinical education