Performance load testing and structural adequacy evaluation of road bridge decks

Many ageing road bridges, particularly timber bridges, require urgent improvement due to the demand imposed by the recent version of the Australian bridge loading code, AS 5100. As traffic volume plays a key role in the decision of budget allocations for bridge refurbishment/ replacement, many bridges in low volume traffic network remain in poor condition with axle load and/ or speed restrictions, thus disadvantaging many rural communities. This thesis examines an economical and environmentally sensible option of incorporating disused flat rail wagons (FRW) in the construction of bridges in low volume, high axle load road network. The constructability, economy and structural adequacy of the FRW road bridge is reported in the thesis with particular focus of a demonstration bridge commissioned in regional Queensland. The demonstration bridge comprises of a reinforced concrete slab (RCS) pavement resting on two FRWs with custom designed connection brackets at regular intervals along the span of the bridge. The FRW-RC bridge deck assembly is supported on elastomeric rubber pads resting on the abutment. As this type of bridge replacement technology is new and its structural design is not covered in the design standards, the in-service structural performance of the FRW bridge subjected to the high axle loadings prescribed in AS 5100 is examined through performance load testing. Both the static and the moving load tests are carried out using a fully laden commonly available three-axle tandem truck. The bridge deck is extensively strain gauged and displacement at several key locations is measured using linear variable displacement transducers (LVDTs). A high speed camera is used in the performance test and the digital image data are analysed using proprietary software to capture the locations of the wheel positions on the bridge span accurately. The wheel location is thus synchronised with the displacement and strain time series to infer the structural response of the FRW bridge. Field test data are used to calibrate a grillage model, developed for further analysis of the FRW bridge to various sets of high axle loads stipulated in the bridge design standard. Bridge behaviour predicted by the grillage model has exemplified that the live load stresses of the FRW bridge is significantly lower than the yield strength of steel and the deflections are well below the serviceability limit state set out in AS 5100. Based on the results reported in this thesis, it is concluded that the disused FRWs are competent to resist high axle loading prescribed in AS 5100 and are a viable alternative structural solution of bridge deck in the context of the low volume road networks.

Reactive image-based collision avoidance system for unmanned aircraft systems

Approximately 20 years have passed now since the NTSB issued its original recommendation to expedite development, certification and production of low-cost proximity warning and conflict detection systems for general aviation [1]. While some systems are in place (TCAS [2]), ¡¨see-and-avoid¡¨ remains the primary means of separation between light aircrafts sharing the national airspace. The requirement for a collision avoidance or sense-and-avoid capability onboard unmanned aircraft has been identified by leading government, industry and regulatory bodies as one of the most significant challenges facing the routine operation of unmanned aerial systems (UAS) in the national airspace system (NAS) [3, 4]. In this thesis, we propose and develop a novel image-based collision avoidance system to detect and avoid an upcoming conflict scenario (with an intruder) without first estimating or filtering range. The proposed collision avoidance system (CAS) uses relative bearing ƒÛ and angular-area subtended ƒê , estimated from an image, to form a test statistic AS C . This test statistic is used in a thresholding technique to decide if a conflict scenario is imminent. If deemed necessary, the system will command the aircraft to perform a manoeuvre based on ƒÛ and constrained by the CAS sensor field-of-view. Through the use of a simulation environment where the UAS is mathematically modelled and a flight controller developed, we show that using Monte Carlo simulations a probability of a Mid Air Collision (MAC) MAC RR or a Near Mid Air Collision (NMAC) RiskRatio can be estimated. We also show the performance gain this system has over a simplified version (bearings-only ƒÛ ). This performance gain is demonstrated in the form of a standard operating characteristic curve. Finally, it is shown that the proposed CAS performs at a level comparable to current manned aviations equivalent level of safety (ELOS) expectations for Class E airspace. In some cases, the CAS may be oversensitive in manoeuvring the owncraft when not necessary, but this constitutes a more conservative and therefore safer, flying procedures in most instances.

Towards an automatic system for road lane marking extraction in large-scale aerial images acquired over rural areas by hierarchical image analysis and Gabor filter

An automatic approach to road lane marking extraction from high-resolution aerial images is proposed, which can automatically detect the road surfaces in rural areas based on hierarchical image analysis. The procedure is facilitated by the road centrelines obtained from low-resolution images. The lane markings are further extracted on the generated road surfaces with 2D Gabor filters. The proposed method is applied on the aerial images of the Bruce Highway around Gympie, Queensland. Evaluation of the generated road surfaces and lane markings using four representative test fields has validated the proposed method.

Speckle reduction in optical coherence tomography imaging by affine-motion image registration

Signal-degrading speckle is one factor that can reduce the quality of optical coherence tomography images. We demonstrate the use of a hierarchical model-based motion estimation processing scheme based on an affine-motion model to reduce speckle in optical coherence tomography imaging, by image registration and the averaging of multiple B-scans. The proposed technique is evaluated against other methods available in the literature. The results from a set of retinal images show the benefit of the proposed technique, which provides an improvement in signal-to-noise ratio of the square root of the number of averaged images, leading to clearer visual information in the averaged image. The benefits of the proposed technique are also explored in the case of ocular anterior segment imaging.

Educational change and youth voice: Informing school action on cyberbullying

Change is a regular part of school life. Educational innovations are constantly being implements in order to benefit students, improve outcomes and meet the obligations and accountability demands of governments. Rapid social and technological change has occurred within and around schools during the past 15 or more years, impacting upon curricula and pedagogies. Simultaneously, there has been a trend towards incorporating youth voice, where young people share in the decisions that will impact on their school experiences (Mitra, 2008a, 2004). Most recently, with the advent of the first National Australian Curriculum (McGaw, 2010), there is an imposed curriculum change, which reflects the growing global trend towards centralised control over what students learn in school (Zhao, 2011) and highlights that schools have to respond to change from all levels. Spears (in press) also notes that parents are raising children in an increasingly wireless world which is far removed from the one in which they were raised. Educators are teaching in schools that are vastly different technologically from those they knew as children and adolescents, or even those in which they were teaching a decade ago. Children born in 1995, the year when the Internet was first commercialised, are 16 years old in 2011 and, whilst parents may have embraced technological advances in their own adult working or social lives, they are yet to fathom fully what it means for their children and their relationships: to be educated and to socialise in the midst of mobile social media. Young people have greater access to more information than at any time past and move seamlessly between online and offline environments, often referring to them as ‘the same life’ (Spears, Kofoed, Bartolo, Palermiti and Castabile, in press). Along with these changes has come the transformation of traditional forms of bullying to cyberbullying, amid the public perception that bullying generally is becoming worse in schools.

Engaging the practice of yarning in Action Research

This paper discusses the technique of ‘yarning’ as an action research process relevant for policy development work with Aboriginal peoples. Through a case study of an Aboriginal community-based smoking project in the Australian State of Victoria, the paper demonstrates how the Aboriginal concept of ‘yarning’ can be used to empower people to create policy change that not only impacts on their own health, but also impacts on the health of others and the Aboriginal organisation for which they work. The paper presents yarning within the context of models of empowerment and a methodological approach of participatory action research. The method is based on respect and inclusivity, with the final policy developed by staff for staff. Yarning is likely to be successful for action researchers working within a variety of Indigenous contexts.

PAR/RAP : Action Research/Research Action Participation

This is a creative piece inspired within and by the decolonising stream that emerged at the World Congress on Action Research and Action Learning, held in Melbourne, Australia in September 2010. It compliments the other works within ALAR Journal's specific edition on research experiences within the decolonising space.

Editorial : Decolonising action research

This edition of the ALAR Action learning action research journal aims to capture some of the current dilemmas, solutions and actions researchers experience in the decolonising space. This collection of papers demonstrates that researchers are not only undertaking action research with and within Indigenous and non-Indigenous contexts, but that they are doing so in exciting and dynamic ways across a diversity of situations. First we will address some of the literature on decolonisation. Then we will explain how this specific edition of the Journal came to fruition and aspects of action research. This is a condensed version of the Editorial that appears in the electronic version of the Journal.

Towards participatory action design research : adapting action research and design science research methods for urban informatics

This paper proposes a new research method, Participatory Action Design Research (PADR), for studies in the Urban Informatics domain. PADR supports Urban Informatics research in developing new technological means (e.g. using mobile and ubiquitous computing) to resolve contemporary issues or support everyday life in urban environments. The paper discusses the nature, aims and inherent methodological needs of Urban Informatics research, and proposes PADR as a method to address these needs. Situated in a socio-technical context, Urban Informatics requires a close dialogue between social and design-oriented fields of research as well as their methods. PADR combines Action Research and Design Science Research, both of which are used in Information Systems, another field with a strong socio-technical emphasis, and further adapts them to the cross-disciplinary needs and research context of Urban Informatics.

Applications of medical image processing in the diagnosis and treatment of spinal deformity

In Chapter 10, Adam and Dougherty describe the application of medical image processing to the assessment and treatment of spinal deformity, with a focus on the surgical treatment of idiopathic scoliosis. The natural history of spinal deformity and current approaches to surgical and non-surgical treatment are briefly described, followed by an overview of current clinically used imaging modalities. The key metrics currently used to assess the severity and progression of spinal deformities from medical images are presented, followed by a discussion of the errors and uncertainties involved in manual measurements. This provides the context for an analysis of automated and semi-automated image processing approaches to measure spinal curve shape and severity in two and three dimensions.

me as al, you as bobby, me as bobby, you as al

In ‘me as al, you as bobby, me as bobby, you as al’, appropriated footage is looped and supplemented with superimposed text, creating a scenario where Robert De Niro and Al Pacino endlessly stalk each other, with their readied-guns chased by hovering words. These titans of Hollywood screen acting represent opposing approaches to the construction of filmic identity, and as the text labels loosely adhere to one weapon and the next, the action on screen becomes an investigation of the subjective and objective potential within screen surrogate constructions of personalized identity. The work was included in the group show 'Vernacular Terrain' (curated by Lubi Thomas and Steven Danzig) for the Songzhuang Art Museum, Beijing.

Determination of stress-strain characteristics of railhead steel using image analysis

True stress-strain curve of railhead steel is required to investigate the behaviour of railhead under wheel loading through elasto-plastic Finite Element (FE) analysis. To reduce the rate of wear, the railhead material is hardened through annealing and quenching. The Australian standard rail sections are not fully hardened and hence suffer from non-uniform distribution of the material property; usage of average properties in the FE modelling can potentially induce error in the predicted plastic strains. Coupons obtained at varying depths of the railhead were, therefore, tested under axial tension and the strains were measured using strain gauges as well as an image analysis technique, known as the Particle Image Velocimetry (PIV). The head hardened steel exhibit existence of three distinct zones of yield strength; the yield strength as the ratio of the average yield strength provided in the standard (σyr=780MPa) and the corresponding depth as the ratio of the head hardened zone along the axis of symmetry are as follows: (1.17 σyr, 20%), (1.06 σyr, 20%- 80%) and (0.71 σyr, > 80%). The stress-strain curves exhibit limited plastic zone with fracture occurring at strain less than 0.1.

Effect of topic domain and task type on Web image searching

Many user studies in Web information searching have found the significant effect of task types on search strategies. However, little attention was given to Web image searching strategies, especially the query reformulation activity despite that this is a crucial part in Web image searching. In this study, we investigated the effects of topic domains and task types on user’s image searching behavior and query reformulation strategies. Some significant differences in user’s tasks specificity and initial concepts were identified among the task domains. Task types are also found to influence participant’s result reviewing behavior and query reformulation strategies.

Just do it : action's central role in venture creation

This study examined the effect that venture creation action has on the outcomes of nascent entrepreneurship. A theoretical model was developed which proposes action as a fundamental mechanism in venture creation. Thus, action should rightly be considered as a means rather than an end in itself. In this respect, action transmits the effects of venture resource endowments on to venture creation outcomes. This conceptual model was empirically supported in a random sample of nascent ventures. Ventures with higher levels of human or social capital tend to be more active in venture creation. In turn, more active venture attempts are more likely to achieve improved results.