Formal Verification of Nonlinear Inequalities with Taylor Interval Approximations

We present a formal tool for verification of multivariate nonlinear inequalities. Our verification method is based on interval arithmetic with Taylor approximations. Our tool is implemented in the HOL Light proof assistant and it is capable to verify multivariate nonlinear polynomial and non-polynomial inequalities on rectangular domains. One of the main features of our work is an efficient implementation of the verification procedure which can prove non-trivial high-dimensional inequalities in several seconds. We developed the verification tool as a part of the Flyspeck project (a formal proof of the Kepler conjecture). The Flyspeck project includes about 1000 nonlinear inequalities. We successfully tested our method on more than 100 Flyspeck inequalities and estimated that the formal verification procedure is about 3000 times slower than an informal verification method implemented in C++. We also describe future work and prospective optimizations for our method.Comment: 15 page

TERA- A Tool for Aero-engine Modelling and Management

One of the distinguishing features of the civil aero-engine market is its high competitiveness. The costs and risks associated with new projects are such that the difference between two apparently equally attractive options could result in success from one and a threat to the survival of the company from the other. To conceive and assess engines with minimum global warming impact and lowest cost of ownership in a variety of emission legislation scenarios, emissions taxation policies, fiscal and Air Traffic Management environments, a Techno-economic and Environmental Risk Assessment (TERA) model is needed. TERA incorporates multi-disciplinary modules for modelling gas turbine and aircraft performance, estimation of engine weight, noise and emissions as well as environment impact and operating economics. The TERA software is integrated with a commercial optimiser and provides a means for cycle studies. It is to be expected that new legislative and fiscal constraints on air travel will demand an extension to the customary range of asset management parameters. In such a business environment there is potential for TERA to develop into a useful tool for aircraft and engine asset management. This paper presents a description of this tool as well as gives some results from scenario studies

Improving forensic casework analysis and interpretation of gunshot residue (GSR) evidence

University of Technology, Sydney. Faculty of Science.There are two main challenges to gunshot residue (GSR) evidence. The first concerns analysis. The lack of screening techniques complicates sampling and analysis of large areas or numbers of exhibits. Also, lead or heavy metal free ammunitions present limitations to the technique for confirmatory detection of residues - scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX). A screening technique was developed to detect GSR components from all ammunition types. Ion mobility spectrometry (IMS) was proven to allow sensitive and effective screening before proceeding to confirmatory analysis. Lead and heavy metal free ammunitions were examined and a technique developed for detecting components in the organic portion of the residue. Liquid chromatography tandem mass spectrometry (LC-MS/MS) was extremely effective, detecting twenty seven components. The technique is sensitive (to around 1 ppb ), selective, rapid and cost effective. The combination of IMS, SEM/EDX and LC-MS/MS, with visual, physica] and microscopic examination, is proposed as a complete protocol for GSR analysis from all ammunition types. The second challenge involves interpretation. Factors that lead to positive and negative findings must be considered and the weight of evidence assessed. Both background data and application of an interpretive framework have been inadequate. Background levels of GSR in the NSW general population and NSW Police Force were studied and the chances of random presence on a suspect and of contamination during arrest and sampling process determined. Nil GSR was detected on hands of the NSW general population or the sample of general duties police officers. A moderate probability was demonstrated for low levels of GSR on hands of crime scene investigators. GSR was detected on hands of all forensic firearms examiners tested, however their role limits access to suspects and items sampled for GSR, limiting the chance of contamination. Significantly, one high risk area for contamination was identified, the tactical response officers. Background levels of GSR in the Australian Federal Police laboratories were compared before and after implementing contamination controls. The configuration of the original laboratory along with the lack of controls lead to GSR being detected on almost every sample. The newer laboratory was extremely clean, only one GSR particle being detected, demonstrating the importance of effective contamination controls during sample collection and analysis. A statistical interpretive framework was developed. The model utilises Bayesian networks to consider existing data relating to transfer and persistence, and new data from this research, providing more objective assessment and allowing broader application of the Bayesian framework

Messing up research: A dialogical account of gender, reflexivity, and governance in auto-ethnography

This paper aims to contribute to a growing critical and reflexive awareness of the implications of gendered assumptions about ontology, epistemology, and ethics in academic research governance and practice. It provides a retrospective account of the authors' shared experiences of an autoethnographic study of lap dancing clubs, focusing on critical or “sticky moments” encountered, and considering the implications of these for research more widely. It does so by highlighting the gendered power relations shaping academic research, showing how Judith Butler's critique of the heterosexual matrix can be applied to a critical, reflexive understanding of the impact of binary, hierarchical gender power relations. The analysis provides insight into some of the ways in which autoethnographic research on sexualized work may become messy, dirty, and sticky in ways that accentuate power inequalities but also open up moments of opportunity for gender binaries and hierarchies to be revealed, challenged, and resisted. Using a Butlerian lens to reflect on our experiences, we contribute to understanding how heteronormative assumptions shape perceptions of what makes “good,” “clean,” and ethically (formally) approved research that conforms to the governmental norms of the heterosexual matrix and, by implication, those contaminating forms of research that disrupt or resist its disciplinary effects. As ethnographic research is often messy by its very nature, and particularly so when situated within sex/sexualized work, we aim to show how gendered assumptions can inhibit reflexivity in academic knowledge production, resulting in research processes that are (paradoxically) unethical. In response, we suggest three ways in which gender reflexive research might be pursued, by: (i) identifying gendered assumptions reflexively and dialogically, (ii) adopting an anti-essentialist approach that foregrounds experiential, embodied knowledge, and (iii) developing an anti-hierarchical methodology. We do so in the hope of opening up ways that might enable others to avoid heteronormative assumptions having potentially detrimental consequences for their research and to offer a starting point for developing gender reflexive knowledge production in the future

Array-based iterative measurements of SmKS travel times and their constraints on outermost core structure

Vigorous convection in Earth's outer core led to the suggestion that it is chemically homogeneous. However, there is increasing seismic evidence for structural complexities close to the outer core's upper and lower boundaries. Both body waves and normal mode data have been used to estimate a P wave velocity, V_p, at the top of the outer core (the E’ layer), which is lower than that in the Preliminary Reference Earth Model. However, these low V_p models do not agree on the form of this velocity anomaly. One reason for this is the difficulty in retrieving and measuring SmKS arrival times. To address this issue, we propose a novel approach using data from seismic arrays to iteratively measure SmKS-SKKS-differential travel times. This approach extracts individual SmKS signal from mixed waveforms of the SmKS series, allowing us to reliably measure differential travel times. We successfully use this method to measure SmKS time delays from earthquakes in the Fiji‐Tonga and Vanuatu subduction zones. SmKS time delays are measured by waveform cross correlation between SmKS and SKKS, and the cross‐correlation coefficient allows us to access measurement quality. We also apply this iterative scheme to synthetic SmKS seismograms to investigate the 3‐D mantle structure's effects. The mantle structure corrections are not negligible for our data, and neglecting them could bias the V_p estimation of uppermost outer core. After mantle structure corrections, we can still see substantial time delays of S3KS, S4KS, and S5KS, supporting a low V_p at the top of Earth's outer core

Atomic Gas in Debris Discs

We have conducted a search for optical circumstellar absorption lines in the spectra of 16 debris disc host stars. None of the stars in our sample showed signs of emission line activity in either H$_{\alpha}$, Ca II or Na I, confirming their more evolved nature. Four stars were found to exhibit narrow absorption features near the cores of the photospheric Ca II and Na I D lines (when Na I D data were available). We analyse the characteristics of these spectral features to determine whether they are of circumstellar or interstellar origins. The strongest evidence for circumstellar gas is seen in the spectrum of HD110058, which is known to host a debris disc observed close to edge-on. This is consistent with a recent ALMA detection of molecular gas in this debris disc, which shows many similarities to the $\beta$ Pictoris system.Comment: Accepted 13/12/2016. Received 2/12/2016; Deposited on 22/11/2016. - 13 Pages, 9 Figures - MNRAS Advance Access published December 15, 201

Detecting the Rise and Fall of 21 cm Fluctuations with the Murchison Widefield Array

We forecast the sensitivity with which the Murchison Widefield Array (MWA) can measure the 21 cm power spectrum of cosmic hydrogen, using radiative transfer simulations to model reionization and the 21 cm signal. The MWA is sensitive to roughly a decade in scale (wavenumbers of k ~ 0.1 - 1 h Mpc^{-1}), with foreground contamination precluding measurements on larger scales, and thermal detector noise limiting the small scale sensitivity. This amounts primarily to constraints on two numbers: the amplitude and slope of the 21 cm power spectrum on the scales probed. We find, however, that the redshift evolution in these quantities can yield important information about reionization. Although the power spectrum differs substantially across plausible models, a generic prediction is that the amplitude of the 21 cm power spectrum on MWA scales peaks near the epoch when the intergalactic medium (IGM) is ~ 50% ionized. Moreover, the slope of the 21 cm power spectrum on MWA scales flattens as the ionization fraction increases and the sizes of the HII regions grow. Considering detection sensitivity, we show that the optimal MWA antenna configuration for power spectrum measurements would pack all 500 antenna tiles as close as possible in a compact core. The MWA is sensitive enough in its optimal configuration to measure redshift evolution in the slope and amplitude of the 21 cm power spectrum. Detecting the characteristic redshift evolution of our models will confirm that observed 21 cm fluctuations originate from the IGM, and not from foregrounds, and provide an indirect constraint on the volume-filling factor of HII regions during reionization. After two years of observations under favorable conditions, the MWA can constrain the filling factor at an epoch when ~ 0.5 to within roughly +/- 0.1 at 2-sigma.Comment: 14 pages, 9 figures, submitted to Ap

Improving labour relations performance using a Simplified Drum Buffer Rope (S-DBR) technique

The purpose of this research is to describe an implementation of Simplified Drum Buffer Rope (S-DBR), a scheduling methodology under Theory of Constraints, in service operations of a US military base. In doing so, this research contributes in two ways. For practitioners, this research is the first to show how S-DBR methodology can be utilised to improve the performance of labour relations. For academicians, this research is one of only a few to address the how questions of S-DBR use in a service context

Lean Systems: Soft OR in practice

Lean implementation involves eliminating all forms of waste (for example, defects or overproduction) and consists of many improvement strategies or systems such as mistake proofing (Poka-Yoke) and Single Minute Exchange of Die (a.k.a. quick changeover). The purpose of this study is to discuss a successful lean or waste elimination initiative for a building products company. Specifically, this study describes how mistake proofing and quick changeover systems were implemented using soft OR practices or Soft Systems Methodology (SSM). Essentially, SSM consisted of four sequential stages, namely (1) problem identification, (2) basic approaches to improvement, (3) making plans for improvement, and (4) translating improvement plans into reality. The study contributes in two ways: for practicing managers, it shows that at the core of lean is soft OR practices, and for academicians, it provides directions for future research