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Reverse domain adaptation for indoor camera pose regression
No full textSynthetic images have been used to mitigate the scarcity of annotated data for training deep learning approaches, followed by domain adaptation that reduces the gap between synthetic and real images. One such approach is using Generative Adversarial Networks (GANs) such as CycleGAN to bridge the domain gap where the synthetic images are translated into real-looking synthetic images that are used to train the deep learning models. In this article, we explore the less intuitive alternate strategy for domain adaption in the reverse direction; i.e., real-to-synthetic adaptation. We train the deep learning models with synthetic data directly, and then during inference we apply domain adaptation to convert the real images to synthetic-looking real images using CycleGAN. This strategy reduces the amount of data conversion required during the training, can potentially generate artefact-free images compared to the harder synthetic-to-real case, and can improve the performance of deep learning models. We demonstrate the success of this strategy in indoor localisation by experimenting with camera pose regression. The experimental results indicate an improvement in localisation accuracy is observed with the proposed domain adaptation as compared to the synthetic-to-real adaptation.</p
Biosynthetic constraints on amino acid synthesis at the base of the food chain may determine their use in higher-order consumer genomes
No full textDietary nutrient composition is essential for shaping important fitness traits and behaviours. Many organisms are protein limited, and for Drosophila melanogaster this limitation manifests at the level of the single most limiting essential Amino Acid (AA) in the diet. The identity of this AA and its effects on female fecundity is readily predictable by a procedure called exome matching in which the sum of AAs encoded by a consumer’s exome is used to predict the relative proportion of AAs required in its diet. However, the exome matching calculation does not weight AA contributions to the overall profile by protein size or expression. Here, we update the exome matching calculation to include these weightings. Surprisingly, although nearly half of the transcriptome is differentially expressed when comparing male and female flies, we found that creating transcriptome-weighted exome matched diets for each sex did not enhance their fecundity over that supported by exome matching alone. These data indicate that while organisms may require different amounts of dietary protein across conditions, the relative proportion of the constituent AAs remains constant. Interestingly, we also found that exome matched AA profiles are generally conserved across taxa and that the composition of these profiles might be explained by energetic and elemental limitations on microbial AA synthesis. Thus, it appears that ecological constraints amongst autotrophs shape the relative proportion of AAs that are available across trophic levels and that this constrains biomass composition.</p
Novel Capping Layer for Foundations in Expansive Soils Using Sustainable Materials
No full textExpansive soils are found all over the world. These soils are highly plastic and can cause damage to infrastructure, building foundations, and roads due to their low strength, high compressibility, and volumetric changes. The behaviour of expansive soils is sensitive to moisture changes, which can lead to significant problems for structures built on them. Building on weak expansive soils is challenging because of their low bearing capacity and susceptibility to volume changes under moisture fluctuations. Expansive soil uplift pressure can cause significant swelling pressure on foundations, while clay shrinkage can lead to substantial foundation settlement during dry seasons. These differential movements can cause damage to the building's superstructure, leading to service and ultimate limit state failures. To mitigate such adverse behaviour on structures, the underlying clay needs improvement before supporting the structural foundations. This research focuses on improving the bearing capacity and volumetric response of expansive soils using sustainable additives.
The traditional method of treating expansive soils with calcium-based additives has been associated with concerns over cost and environmental impact. However, this study proposes the use of recycled materials like glass and fly ash as secondary additives to improve the properties of expansive soils in subgrades and foundations. Several mechanical tests, including the Standard Compaction Test, Unconfined Compressive Strength (UCS) test, and Direct Shear Test, were conducted to assess the behaviour of various additives, along with microscopic tests like SEM, XRD, FTIR, TGA, and porosity, and a hydraulic conductivity test (permeability). The study also explored the impact of secondary additives like Class F fly ash, lime, CSA cement, enzyme, recycled concrete, and polymers on improving the expansive soil behaviour.
Through advanced microscopical analysis techniques, we were able to evaluate the effectiveness of chemical additives, glass aggregate, and powder in soil stabilisation. The combination of secondary additives with clay showed promising results in terms of mechanical behaviour, but the addition of glass waste further improved the density, UCS, and frictional characteristics of the stabilised soil mix. While changes in the chemical composition were detected in soil mixed with secondary additives, the addition of glass had little effect. These findings provide insight into how standard stabilisers can be utilised with waste glass to enhance the hydro-mechanical characteristics of expansive soils. Specifically, this research shows that the stabilised soil-glass matrix, derived from secondary additives, increases the bearing capacity of expansive weak clays and offers a sustainable solution for managing glass waste.
The results of the optimum stabilisation mix were verified by conducting proto-type model tests simulating foundational loads in order to propose a new method for improving the stability and moisture control of foundations. A capping layer was added underneath the foundation using a recycled glass-based stabilisation approach. A prototype foundation was constructed, and its performance was monitored in the laboratory under various moisture and load conditions over one year. The results showed that the capping layered foundation outperformed the traditional foundation in terms of stability and moisture control, even during seasonal fluctuations. The outcome of this research proposes a sustainable foundation construction process using recycled glass wastes, which could significantly improve the performance of foundations in expansive soils.</p
The Spread and Origins of the German Proportionality Doctrine
No full textThe three-part proportionality test (suitable, necessary and adequacy in balance) developed by Germany’s Federal Constitutional Court has conquered the world. But almost nothing is known of its origins. This essay proposes, on the basis of several items of circumstantial evidence, that Gerhard Leibholz (1901 – 1982), Judge of the Court from 1951 to 1971 and professor of law, may have had the leading role in its development. His early writings from the mid-1920s strikingly presage the development of the test; it suited his broader judicial agenda; he was a Judge when it was developed, even if on the “wrong” side of the Court; and it was developed in an area of law in which he was the acknowledged expert.</p
Applications of Textile-Based Compression for Human Spacefight and Extraterrestrial Surface Exploration
No full textThe objective of this chapter is to provide a general introduction to two applications of textile-based compression: (1) mechanical counterpressure extra-vehicular activity suits and (2) mechanical-loading countermeasure garments. First, in space or on extraterrestrial surfaces, humans require sufficient pressure applied to the surface of the body and historically, gas-pressurized suits have been used. For reasons including lower mass and the potential for improved mobility, particularly for surface exploration missions, using textile-based compression (mechanical counterpressure) has been proposed as an alternative suit architecture. Second, the mechanical and interrelated hydrostatic unloading of the human body in microgravity or partial gravity drives physiological responses and adaptations that can be problematic for a return to higher gravity (e.g., returning to Earth or arriving on Mars after transit in microgravity). Specialized compression garments have existing and proposed roles in supporting selected aspects of physiological function during transient stress (e.g., for orthostatic intolerance) and in preventing or mitigating physiological changes in microgravity that arise from a lack of body weight and associated axial load.</p
Wraparound service co-design: supporting sustainable employment of ethnic and culturally diverse communities
No full textThis report explores the key findings from the research and presents a way forward through a proposed framework for wraparound services. The framework is built on a set of overarching principles which should guide further work to promote employment access and opportunity. These principles will ensure that strategy and service development is centred around the lived experience of individuals and community, cocreating and tailoring solutions with the workforce and around the person, whilst also addressing structural change.</p
Validation testing of a language translation device for suitability in assisting Australian radiation therapists to communicate with Mandarin-speaking patients
No full textIntroduction: Clear, timely communication between practitioners and patients is key in ensuring equitable access to health services and optimal care. Australia's linguistically diverse population adds complexity to healthcare provision. This paper describes a validation study to assess clinical suitability of a language translation device, intended for use with Mandarin speaking patients undergoing radiotherapy (RT). Materials and methods: After a comprehensive device selection process, common phrases used in RT practice were curated within one clinical center and translated by interpreters. Phrases were categorized by conversation type and readability (according to Flesch-Kincaid and FORCAST scores). Validation of device performance was undertaken by purposely selected radiation therapists (RTTs) who tested and evaluated the device using a survey with 5-point Likert scale responses. Statistical analysis was undertaken on Excel using Pearson's chi-square, z-test, interrater reliability/agreement and linear regression analyses. Results: Six RTTs and two interpreters volunteered to participate in this study. 188 common phrases were spoken verbatim into the device and scored on a 5-point Likert scale, yielding an overall output accuracy of 66%. A z-test confirmed significance against prior comparative research and Linear regression analysis observed improved output between consecutive participants. 62.7% of interpreter scores were identical; a further 29.1% constituted a single point scoring variation. Poorer outcomes were observed with colloquial English and lower readability. Conclusions: This study found the device produced suitable translation accuracy and identified language styles that should be avoided with use. Further research could consider clinical application, expanded languages and/or health disciplines, and development of a national RTT phrase list.</p
Two-dimensional Molybdenum Oxide in Optical Applications
No full textThe emerging two-dimensional (2D) nanomaterials with atomic thicknesses and large surface-to-volume ratios exhibit outstanding optical properties which makes them promising candidates for next-generation miniatured on-chip devices. Although a few ultrathin materials with layered structures have been identified after the discovery of graphene, the members of the 2D realm are still insufficient to meet the requirement for nanotechnology development. Metal oxides are a group of earth-abundant material which has unique electronic and optical properties, and great chemical stability. Their 2D forms have attracted increasing attention owing to their great tunability in the band structure and optical responses, which expand the library of 2D materials. However, the current synthesis methods of 2D metal oxides are obstructed by the trade-off among the film quality, lateral dimensions, contamination introduced, and yield, hindering the comprehensive studies on their properties and the opportunities for further utilisation in practical applications.
Therefore, the author of this thesis focuses on the research in facile synthesis of large-area, high-quality 2D metal oxides and fundamental studies of their tunable chemical composition and optical properties, along with the realisation of their potential in novel applications, especially compact optics. Molybdenum oxide (MoOx) is selected for this PhD research due to its diverse stoichiometries which result in extensive tunability in electronic and optical properties, presenting a solid ground for the exploration and advancement in the field.
The research work started by exploring different synthesis approaches that can acquire high-quality, contamination-free 2D MoOx nanomaterials. A novel “stamping” method adopted from the concept of metal-gas interface reaction on the metal surface is applied first. Highly crystalline MoO3 nanosheets in a special hexagonal phase with a thickness down to ~2 nm are obtained using this method. Moreover, the physical vapour deposition (PVD) method is proposed to synthesise ultrathin 2D MoOx films with up to a wafer-scale lateral dimension. The smooth and uniform amorphous films synthesised have a thickness of ~10 nm. MoOx (2.7 < x < 3) enjoys controllable optical properties depending on its stoichiometric state which is manipulated by the precise redox treatments where the refractive index (n) and absorption coefficient (k) are tuned accordingly. The ellipsometer measurements indicate that a modulation depth of 0.62 in Δn and 0.42 in Δk can be achieved at the communication wavelength between the full stoichiometric MoO3 and the sub-stoichiometric MoO2.7. The significant tunability in optical properties renders the as-synthesised 2D MoOx film light-modulating applications while the PVD synthesis method is highly compatible with existing nanofabrication techniques, encouraging the utilisation of the product in tunable on-chip optics.
After gaining a comprehensive understanding of the optical properties of the as-synthesised 2D MoOx film, the author focuses on the integration of the nanofilms onto the silicon photonic circuit chips. Since the growing demands of compact on-chip optical devices with dynamic responses, the capability of in situ evaluation of the 2D functional materials’ optical parameters is highly desired nowadays. The author proposes a silicon photonics-enabled platform that is capable of evaluating the complex refractive indices of 2D nanomaterials with arbitrary dimensions in a facile and reliable manner. A Mach-Zehnder interferometer (MZI) configuration integrated with MoOx in different stoichiometries is used to demonstrate the influence on the output optical transmission spectrum induced by variations in the complex refractive indices of the sample material. The recorded wavelength shifts of the interference pattern and amplitude changes are used to extract the optical complex refractive indices. The deviation of the measured shifts is as low as 1% and generally less than 5% compared with the theoretical calculation. The proposed platform offers a novel approach for the measurement of the complex refractive index of 2D MoOx with high accuracy and reliability, which can be possibly extended to most of the tunable 2D nanomaterials.
In the final stage of this PhD thesis, the author further investigates the possibilities of employing the ultrathin 2D MoOx nanofilms prepared in the previous steps in planar lens applications. Detailed discussions in terms of the lens theory and operation principles of various planar lenses, including the Fresnel lens, Fresnel zone plate (FZP) and dielectric metalenses, are conducted to identify a suitable design methodology for the MoOx-based lens. After examining the tunability in amplitude and phase responses which are calculated by an RCWA solver based on the optical parameters of the ultrathin MoOx film from 485 to 1550 nm, the author presents the designs of FZPs with operating wavelengths λ at 633 and 1550 nm, respectively. The designed zone plate with λ = 633 nm has an outer radius of 39.71 μm and a numerical aperture (N.A.) of 0.37 while for λ = 1550 nm, the design gives a 63.76 μm-radius zone plate with an N.A. of 0.54. Fabrication of the designed FZP has been carried out as the patterning for the concentric rings of the plate with the finest structure <1 µm has been produced by photolithography technique on a glass substrate. Attempts on the utilisation of 2D MoOx-enabled FZP pave the way for applying the as-prepared MoOx film in tunable ultrathin flat lenses, which also demonstrates its potential in other compact, on-chip imaging devices, such as metasurfaces and holographic applications.
In summary, the author successfully demonstrates several breakthroughs in the realm of 2D tunable metal oxides during her PhD program, covering their controllable synthesis, fundamental characteristics, and practical applications. It is expected that the outcomes of this PhD research work will commit to overcoming the bottlenecks of 2D metal oxide synthesis and lead to high cost-efficiency in optical sensing and imaging platforms with high performance and dynamical tunability.</p
Conformable Sensors for Healthcare and Environmental Sensing Applications
No full textWith quantum leaps in technology in the electronics sector, demand for the miniaturisation of devices while retaining their functionality is on the increase. Such miniaturized sensors, with the ability to be skin-conformable, offers the potential to monitor healthcare and environmental parameters. Environmental parameters such as temperature changes that need to be continuously and accurately monitored requires a highly sensitive material that can accurately detect these changes and also take humidity fluctuations into consideration. Metal oxide-based thermal sensors are desired, owing to their enhanced sensing capabilities and low cost of operation. Highly sensitive metal oxide sensors can enable stable, accurate and miniaturised thermal sensors tailored to different operational ranges. The biggest challenges the healthcare sector faces include the growing workload on healthcare professionals, escalating costs, and lack of continuous medical data. To address these challenges, wearable sensors capable of point-of-care diagnostics are the need of the hour. Unlike their rigid counterparts, which are clunky and predominantly used as non-invasive platforms, conformable sensors facilitate a closer and more intimate anatomical contact between the sensing platform and the human body. By integrating with wireless communication capabilities, continuous monitoring of biometric data and environmental parameters is achievable. The adoption of such conformable sensing devices holds significant potential for revolutionizing monitoring of environmental parameters and healthcare practices by addressing the challenges posed by increasing workloads and rising costs. This work is comprised of three components. In the first part, a vanadium dioxide (VO2)-based thin film thermal sensor was developed and studied under the influence of varying humidity conditions. The effect of different humidity levels on the overall thermal sensing behaviour and the insulator-to-metal transition (IMT) phenomenon was investigated. Further, density functional theory (DFT) studies were conducted to understand the thermal sensing mechanism under changing humidity conditions. The developed sensor exhibited a very good response over a broad temperature range of –100 oC to 100 oC, with a TCR of –0.00243%, high sensitivity and cyclic repeatability. Wireless measurement capabilities were also demonstrated. Such sensors could potentially be used in environmental and wearable sensing applications. The second part focuses on developing a compact and wearable ECG monitor. Among the various biophysical parameters that are of interest in a wearable device, an electrocardiogram (ECG) is critical as it enables detection of cardiovascular-related ailments and assessment of overall cardiac health. In a wearable ECG device, the choice of electrode design and material plays a key role in the performance of the sensor. Various dry electrode-based sensor design geometries have been explored to realise a compact, lightweight, portable, gel-free wearable ECG patch that would aid in point-of-care (PoC) diagnostics. Further, the influence of the region of the body at which the measurements were made was studied under different body positions across varying external stimuli. The influence of surface area, perimeter and resistance offered by the electrodes on the ECG signal acquisition, its effects on device performance were investigated and it was concluded that the hexagonal labyrinth configuration was the most suitable candidate. A prototype of a wearable ECG patch was made by combining this electrode configuration and interfacing it with wireless communication capabilities, and the results were compared with commercially available portable ECG monitor. Such a device could find potential application in remote healthcare and ambulatory care settings, and as a PoC and a preventive medical device. Finally, the third part focuses on developing a wearable cutaneous wound healing monitor, specifically for monitoring the wound healing progression in chronic wounds. A unique approach employing a multiplexed combination of SMD temperature sensors, thin-pH sensors, and conductometric biosensors employing highly resistive Silicon (HR-Si) technology to monitor proteins key to wound healing indication such as C-reactive protein and Interleukin-6 concentrations was developed to monitor the progression (or lack thereof) of chronic wound healing. This helps to monitor the various phases of wound healing such as haemostasis, inflammation, proliferation, and remodelling. Normal skin and healed wounds typically have temperature between 31.10 oC – 35.40 oC. Wounded skin when healing has a temperature between 36.0 oC – 38.0 oC. Any temperature >38.0 oC is critical and might lead to amputation. Healthy skin has a pH 7 would indicate the presence of a chronic wound. A CRP concentration of 40 nM, this is a sure sign that chronic wound infection is getting worse. Similarly, an IL-6 concentration of 45 nM indicates that the wound is getting adverse. By using a triangulated approach of combining miniaturized temperature, pH, CRP, and IL-6 sensors, accurate and continuous monitoring wound healing at the site of inspection is possible. This developed sensor was found to efficiently monitor the changes in these biophysical parameters and the protein biomarkers under ideal conditions and also under the influence of fluctuating temperature. Further, this cutaneous wound healing monitor was enabled with wireless NFC capabilities which helps in its application as a PoC diagnostic device. The findings related to these studies is expected to potentially lead to the development of an entire system of sensors for monitoring healthcare and environmental parameters.</p
Phase separation in a ternary DPPC/DOPC/POPC system with reducing hydration
No full textThe maintenance of plasma membrane structure is vital for the viability of cells. Disruption of this structure can lead to cell death. One important example is the macroscopic phase separation observed during dehydration associated with desiccation and freezing, often leading to loss of permeability and cell death. It has previously been shown that the hybrid lipid 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) can act as a line-active component in ternary lipid systems, inhibiting macroscopic phase separation and stabilising membrane microdomains in lipid vesicles [1]. The domain size is found to decrease with increasing POPC concentration until complete mixing is observed. However, no such studies have been carried out at reduced hydration. To examine if this phase separation is unique to vesicles in excess water, we have conducted studies on several binary and ternary model membrane systems at both reduced hydration (“powder” type samples and oriented membrane stacks) and in excess water (supported lipid bilayers) at 0.2 mol fraction POPC, in the range where microdomain stabilisation is reported. Differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) are used to map phase transition temperatures, with X-ray and neutron scattering providing details of the changes in lipid packing and phase information within these boundaries. Atomic force microscopy (AFM) is used to image bilayers on a substrate in excess water. In all cases, macroscopic phase separation was observed rather than microdomain formation at this molar ratio. Thus POPC does not stabilise microdomains under these conditions, regardless of the type of model membrane, hydration or temperature. Thus we conclude that the driving force for separation under these conditions overcomes any linactant effects of the hybrid lipid.</p