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Common mode voltage elimination in industrial AC-AC converters based on model predictive control
No full textCommon-mode-voltage (CMV) is known for creating bearing currents and electromagnetic interference in industrial drive applications. Additionally, as explained in this paper, in underground earthing environment, CMV has safety implications. To address these problems, the paper performs a comparative evaluation of the two converter options: Matrix Converter (MC) and two-level voltage source inverter (VSI) with Active Front End (AFE). While both topologies transform constant AC input into variable AC output, MC has a weight and size benefit, due to the capacitor downsizing. The paper presents a detailed modelling showing the possibility to completely eliminate CMV in both options. Under the imposed condition of zero CMV, the paper compares performance of the two topologies, with respect to the input and output harmonic distortion and robustness under variable frequency operation. As a control strategy, it implements a Modified Model Predictive Control (MMPC), which allows to significantly reduce the computation time. Based on extensive simulations performed in MATLAB-Simulink environment, the paper makes a recommendation about the most suitable topology for an AC drive in CMV-sensitive underground mining applications. Experimental validation of the paper findings is underway
The fast and the robust: trade-offs between optimization robustness and cost in the calibration of environmental models
No full textEnvironmental modelers using optimization algorithms for model calibration face an ambivalent choice. Some algorithms, for example, Newton‐type methods, are fast but struggle to consistently find global parameter optima; other algorithms, for example, evolutionary methods, boast better global convergence but at much higher cost (e.g., requiring more objective function calls). Trade‐offs between accuracy/robustness versus cost are ubiquitous in numerical computation, yet environmental modeling studies have lacked a systematic framework for quantifying these trade‐offs. This study develops a framework for benchmarking stochastic optimization algorithms in the context of environmental model calibration, where multiple algorithm invocations are typically necessary. We define reliability as the probability of finding the desired (global or tolerable) optimum from random initial points and estimate the number of invocations to find the desired optimum with prescribed confidence (here 95%). A robust algorithm should achieve consistently high reliability across many problems. A characteristic efficiency metric for algorithm benchmarking is defined as the total cost (objective function calls over multiple invocations) to find the desired optimum with prescribed confidence. This approach avoids the pitfalls of existing approaches that compare costs without controlling the confidence in algorithm success. A case study illustrates the framework by benchmarking the Levenberg‐Marquardt and Shuffled Complex Evolution (SCE) algorithms over three catchments and four hydrological models. In 8 of 12 scenarios, Levenberg‐Marquardt is more efficient than SCE—by sacrificing some of its speed advantage to match SCE reliability through more invocations. The proposed framework is easy to apply and can help guide algorithm selection in environmental model calibration
Increasing the provision of preventive care by clinicians within substance use treatment settings
No full textPeople with substance use problems have significantly higher mortality and morbidity rates and reduced life expectancy compared to the general population. Part of this excess mortality and morbidity is attributable to substance use, however a significant proportion is due to higher rates of other preventable chronic illness. A high prevalence of additional modifiable health risk behaviours, specifically tobacco smoking, insufficient fruit and/or vegetable consumption and insufficient physical activity, contributes to such chronic disease levels. Substance use treatment settings are an opportunity for the delivery of preventive care to address modifiable health risk behaviours for people who have substance use problems. Despite this opportunity, relatively little is known about health risks behaviours and preventive care for people attending substance use treatment. Only very limited research has examined the prevalence of health risk behaviours for people with substance use problems; the provision of preventive care by substance use treatment clinicians; and clinical practice change strategies that may be effective in increasing the provision of such care within substance use treatment settings. To address this gap in the knowledge, the broad aims of this thesis were to: 1. Identify the prevalence of three chronic disease health risk behaviours (tobacco smoking, insufficient fruit and vegetable consumption, and insufficient physical activity) among clients of community substance use treatment services. 2. Examine the prevalence of preventive care provision (in the form of assessment, brief advice and referral) for such health risk behaviours in community substance use treatment settings. 3. Explore the potential association between clinician attitudes and beliefs with the provision of preventive care for such health risk behaviours. 4. Determine the effectiveness of a clinical practice change intervention in increasing community substance use treatment clinicians’ provision of preventive care (in the form of assessment, brief advice and referral) for three health risk behaviours (tobacco smoking, insufficient fruit and vegetable consumption, and insufficient physical activity) within community substance use treatment services. To address the above aims, a series of studies was undertaken from 2012 to 2014 within 15 community substance use treatment services in one local health district in New South Wales, Australia. These studies included: a cross-sectional survey of 386 community substance use treatment clients; a cross-sectional survey of 54 community substance use treatment clinicians; and a pre-post multi-strategic clinical practice change pilot intervention trial. The studies were evaluated utilising surveys of clients attending community substance use treatment services over a two-year period and surveys of community substance use treatment clinicians. In addition, a systematic review of the peer-reviewed literature that describes the prevalence of preventive care delivery in substance use setting was undertaken. This thesis contributes significantly to the limited research in this area in several ways. Firstly, this thesis reported a high prevalence of modifiable health risk behaviours (tobacco smoking, insufficient fruit and/or vegetable consumption, insufficient physical activity) in community substance use treatment clients and high client interest in modifying such behaviours. In addition, both community substance use treatment clinicians and clients reported favourable attitudes towards the provision of preventive care within substance use treatment settings. However, the provision of preventive care to address such behaviours was found to be suboptimal for all care elements (assess, advise, refer) for insufficient fruit and/or vegetable consumption and insufficient physical activity and referral for all health risk behaviours. The systematic review, although limited to tobacco smoking care, supported this finding. The review also highlighted a variety of measures currently utilised to record and report the provision of preventive care in substance use treatment settings. Secondly, the multi-strategic clinical practice change intervention that aimed to increase the provision of preventive care in substance use treatment settings had varying impact across elements of care and risk factors. Although an increase in the provision of care for insufficient fruit and/or vegetable consumption was indicated, the intervention had no impact on care for smoking and insufficient physical activity. This thesis identified a need for further research regarding the provision of preventive care for multiple health risk behaviours in substance use treatment settings. It is suggested that future research consider: how the provision of preventive care in substance use treatment settings is measured; the barriers and facilitators to the provision of preventive care; and the use of robust study designs when examining the effectiveness of interventions that aim to increase clinician provision of preventive care
Containment control in extended Taylor model
No full textIn this paper, we propose an extension to Taylor model of opinion dynamics in social networks. Motivated by bounded confidence models, we propose an extended Taylor model in which the influence graph is built based on the confidence levels of individuals. Furthermore, we establish a link between structural controllability of this model and containment of individuals' opinions by the sources. In addition, an algorithm is proposed to find the minimum values of the confidence levels ensuring that structural controllability and containment can be achieved. An illustrative example is provided to verify the proposed scheme
Economic evaluation of telephone-based weight loss support for patients with knee osteoarthritis: a randomised controlled trial
No full textBackground: The prevalence of knee osteoarthritis is increasing worldwide. Obesity is an important modifiable risk factor for both the incidence and progression of knee osteoarthritis. Consequently, international guidelines recommend all patients with knee osteoarthritis who are overweight receive support to lose weight. However, few overweight patients with this condition receive care to support weight loss. Telephone-based interventions are one potential solution to provide scalable care to the many patients with knee osteoarthritis. The objective of this study is to evaluate, from a societal perspective, the cost-utility and cost-effectiveness of a telephone-based weight management and healthy lifestyle service for patients with knee osteoarthritis, who are overweight or obese. Methods: An economic evaluation was undertaken alongside a pragmatic randomised controlled trial. Between May 19 and June 30, 2015, 120 patients with knee osteoarthritis were randomly assigned to an intervention or usual care control group in a 1:1 ratio. Participants in the intervention group received a referral to an existing non-disease specific 6-month telephone-based weight management and healthy lifestyle service. Quality-adjusted life years (QALYs) was the utility measure and knee pain intensity, disability, weight, and body mass index (BMI) were the clinical measures of effect. Costs included intervention costs, healthcare utilisation costs (healthcare services and medication use) and absenteeism costs due to knee pain. Data was collected at baseline, 6 weeks and 26 weeks. The primary cost-effectiveness analysis was performed from the societal perspective.
Results: Mean cost differences between groups (intervention minus control) were -32 (95%CI: -73 to 13) for medication costs, and 1197 (95%CI: -2887 to 6106). For QALYs and all clinical measures of effect, the probability of the intervention being cost-effective compared with usual care was less than 0.36 at all willingness-to-pay values. Conclusions: From a societal perspective, telephone-based weight loss support, provided using an existing non-disease specific 6-month weight management and healthy lifestyle service was not cost-effective in comparison with usual care for overweight and obese patients with knee osteoarthritis
Revised limits of participation in public life: Roman aristocratic women from the late republic to the early imperial period
No full textThis thesis charts the growth in the role of elite Roman women in public life from the period of the Gracchi to the early empire under Augustus. Roman patriarchy excluded women from direct participation in politics in the forum or the Senate, so much emphasis falls on indirect access to power. To review this, two introductory chapters discuss Roman male perceptions of ideal female behaviour, and legislative changes with a direct impact on female lives. This is followed by studies of significant individuals, divided into two groups. The first reviews Cornelia, Clodia, Servilia, and Terentia and Tullia. Cornelia’s life as the mother of revolutionary sons is the sole example from the second century BC, and is followed by key characters from the last generation of the Republic. The second consists of Fulvia and Octavia, women whose status was prominent during the triumvirate as successive wives of the triumvir Antony. Individual lives are tested to establish the extent to which they were pushing the boundaries of ideal behaviour, and to attempt to establish how and why this occurred. Each individual is tested against their adherence to tradition female roles, their advance into areas of controversy, and finally truly transgressive acts. The application of these tests shows that matters advanced over the selected period as areas considered controversial or transgressive modified under changed social and political conditions. Many of the changes occurred informally, as women became involved in political arrangements through extended relevance of the domestic context. Women were initially used as proxies in the late Republic because of frequent absences overseas, but the advent of empire and the imperial court encouraged their use in novel roles
An in-situ data based model to downscale radiometric satellite soil moisture products in the Upper Hunter Region of NSW, Australia
No full textHigh spatial resolution soil moisture information is important for hydrological, climatic and agricultural applications. The lack of high resolution soil moisture data over large areas at the required accuracy is a major impediment for such applications. This study investigates the feasibility of downscaling satellite soil moisture products to 1 km resolution. This study was undertaken in the semi-arid Goulburn River Catchment, located in south-eastern Australia. The Soil Moisture Active Passive (SMAP)-Enhanced 9 km (L3SMP-E) and Soil Moisture and Ocean Salinity (SMOS) 25 km gridded (SMOS CATDS L3 SM 3-DAY) radiometric products were compared with in-situ soil moisture observations and a regression tree model was developed for downscaling based on thermal inertia theory. Observations from a long-term soil moisture monitoring network were employed to develop a regression tree model between the diurnal temperature difference and the daily mean soil moisture for soils with different clay content and vegetation greenness. Moderate-resolution Imaging Spectroradiometer (MODIS) land surface temperatures were used to estimate the soil moisture at high spatial resolution by disaggregating the satellite soil moisture products through the regression model. The downscaled SMAP-Enhanced 9 km and SMOS 25 km gridded soil moisture products showed unbiased root mean square errors (ubRMSE) of 0.07 and 0.05 cm³/cm³, respectively, against the in-situ data. These ubRMSEs include errors caused by measuring instrument and the scale mismatch between downscaled products and in-situ data. An RMSE of 0.07 cm³/cm³ was observed when comparing the downscaled soil moisture against the passive airborne L-band retrievals. The findings here auger well for the use of satellite remote sensing for the assessment of high resolution soil moisture
Strategic planning towards a world-class university
No full textStrategic planning with a focus on world-class university status is an option that cannot be avoided by universities today to survive and succeed in competition as a provider of higher education. The objective of this research is to obtain exploratory research results on the strategic plans of universities that are prepared to generate world-class university status. This research utilised exploratory qualitative research method and data was collected by in-depth interviews method. Interview transcripts were analyzed by using thematic content analysis through NVivo software analysis and manual systems. The main finding of interview shows that most interviewees agreed that UNIMA has been engaged in strategic planning. Contribution from faculties and schools are acknowledged and inform the planning process. However, a new model of strategic planning should be adopted by UNIMA due to the shift towards a "corporate university". The finding results from documents, literature review and interview were the addition of world-class university characteristics and features to current strategic planning of UNIMA and how to upgrade by considering to use the characteristics and features towards world-class university
On the use of GRACE normal equation of intersatellite tracking data for improved estimation of soil moisture and groundwater in Australia
No full textAn accurate estimation of soil moisture and groundwater is essential for monitoring the availability of water supply in domestic and agricultural sectors. In order to improve the water storage estimates, previous studies assimilated terrestrial water storage variation (ΔTWS) derived from the Gravity Recovery and Climate Experiment (GRACE) into land surface models (LSMs). However, the GRACE-derived ΔTWS was generally computed from the high-level products (e.g. time-variable gravity fields, i.e. level 2, and land grid from the level 3 product). The gridded data products are subjected to several drawbacks such as signal attenuation and/or distortion caused by a posteriori filters and a lack of error covariance information. The post-processing of GRACE data might lead to the undesired alteration of the signal and its statistical property. This study uses the GRACE least-squares normal equation data to exploit the GRACE information rigorously and negate these limitations. Our approach combines GRACE's least-squares normal equation (obtained from ITSG-Grace2016 product) with the results from the Community Atmosphere Biosphere Land Exchange (CABLE) model to improve soil moisture and groundwater estimates. This study demonstrates, for the first time, an importance of using the GRACE raw data. The GRACE-combined (GC) approach is developed for optimal least-squares combination and the approach is applied to estimate the soil moisture and groundwater over 10 Australian river basins. The results are validated against the satellite soil moisture observation and the in situ groundwater data. Comparing to CABLE, we demonstrate the GC approach delivers evident improvement of water storage estimates, consistently from all basins, yielding better agreement on seasonal and inter-annual timescales. Significant improvement is found in groundwater storage while marginal improvement is observed in surface soil moisture estimates
Sparse representation using stepwise Tikhonov regularization with offline computations
No full textThis letter describes a novel algorithm for sparse reconstruction. The method uses offline computations to reduce the computational burden of online execution. The approach relies on the recently proposed stepwise Tikhonov regularization (STIR) method to implement forward selection procedures such as orthogonal least squares (OLS), orthogonal matching pursuit (OMP), and STIR. Numerical simulations show the efficacy of the proposed approach, which is competitive against state-of-the-art implementation of OLS and OMP