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    49195 research outputs found

    Spin guides and spin splitters: Waveguide analogies in one-dimensional spin chains

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    Here we show a mapping between waveguide theory and spin-chain transport, opening an alternative approach to solid-state quantum information transport. By applying temporally varying control profiles to a spin chain, we design a virtual waveguide or "spin guide" to conduct spin excitations along defined space-time trajectories of the chain. We show that the concepts of confinement, adiabatic bend loss, and beam splitting can be mapped from optical waveguide theory to spin guides, and hence to "spin splitters." Importantly, the spatial scale of applied control pulses is required to be large compared to the interspin spacing, thereby allowing the design of scalable control architectures

    Integrating Learning into a BDI Agent for Environments with Changing Dynamics

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    We propose a framework that adds learning for improving plan selection in the popular BDI agent programming paradigm. In contrast with previous proposals, the approach given here is able to scale up well with the complexity of the agent's plan library. Technically, we develop a novel confidence measure which allows the agent to adjust its reliance on the learning dynamically, facilitating in principle infinitely many (re)learning phases. We demonstrate the benefits of the approach in an example controller for energy management

    Engaging with ku: From abstraction to meaning through the practice of noticing

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    This paper presents a design project that explored the practice of "noticing". Noticing is a way in and through which we are able to understand and create our relationship to space and place. The practice of noticing can facilitate awareness, reflection, learning and transformation (Mason 2002). Noticing is a practice that enables us to engage with the concept of Ku~, meaning "space", in Japanese. In this project context, Ku~ is interpreted as a space of potentiality rather than emptiness or nothingness. Engaging with Ku~ through the practice of noticing can enable a transition from abstraction to meaning. Ku~ can also be an expression of the ambiguous potential of design investigations: including knowing and the unknown, the limitations and the challenges. To practice design in this way is to step outside of the confines of certainty and embark on an exploratory path of discovery. Just as design is a way of engaging with space - to enunciate the unknown, to create meaning from the abstract - so too is noticing as a temporal practice of discovery and place making. Through the act of noticing the ambiguous openness of space is transformed into the connectedness of place (Casey 2001)

    Bubble popper: considering body contact in games

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    Exertion games, digital games that involve physical effort, are becoming more popular. Although some of these games support social experiences, they rarely consider or support body contact. We believe overlooking body contact as part of social play experiences limits opportunities to design engaging exertion games. To explore this opportunity, we present Bubble Popper, an exertion game that considers and facilitates body contact. Bubble Popper, which uses very simple technology, also demonstrates that considering and facilitating body contact can be achieved without the need to sense body contact. Through reflecting on our design and analyzing observations of play we are able to articulate what impact physical space layout in relation to digital game elements, and physical disparity between input and digital display can have on body contact. Our results aid game designers in creating engaging exertion game experiences by guiding them when considering body contact, ultimately helping players benefiting from more engaging exertion games

    Increased nitric oxide activity compensates for increased oxidative stress to maintain endothelial function in rat aorta in early type 1 diabetes

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    Hyperglycaemia and oxidative stress are known to acutely cause endothelial dysfunction in vitro, but in the initial stages of diabetes, endothelium-dependent relaxation is preserved. The aim of this study was to investigate how endothelium-dependent relaxation is maintained in the early stages of type 1 diabetes. Diabetes was induced in Sprague-Dawley rats with a single injection of streptozotocin (48 mg/kg, i.v.), and after 6 weeks, endothelium-dependent and endothelium-independent relaxations were examined in the thoracic aorta in vitro. Lucigenin-enhanced chemiluminescence was used to measure superoxide generation from the aorta. Diabetes increased superoxide generation by the aorta (2,180 +/- 363 vs 986 +/- 163 AU/mg dry tissue weight)

    Adaptive random testing by exclusion through test profile

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    One major objective of software testing is to reveal software failures such that program bugs can be removed. Random testing is a basic and simple software testing technique, but its failure-detection effectiveness is often controversial. Based on the common observation that program inputs causing software failures tend to cluster into contiguous regions, some researchers have proposed that an even spread of test cases should enhance the failure-detection effectiveness of random testing. Adaptive random testing refers to a family of algorithms to evenly spread random test cases based on various notions. Restricted random testing, an algorithm to implement adaptive random testing by the notion of exclusion, defines an exclusion region around each previously executed test case, and selects test cases only from outside all exclusion regions. Although having a high failure-detection effectiveness, restricted random testing has a very high computation overhead, and it rigidly discards all test cases inside any exclusion region, some of which may reveal software failures. In this paper, we propose a new method to implement adaptive random testing by exclusion, where test cases are simply selected based on a well-designed test profile. The new method has a low computation overhead and it does not omit any possible program inputs that can detect failures. Our experimental results show that the new method not only spreads test cases more evenly but also brings a higher failure-detection effectiveness than random testing

    Activation of AMPK by bitter melon triterpenoids involves CaMKKβ

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    We recently showed that bitter melon-derived triterpenoids (BMTs) activate AMPK and increase GLUT4 translocation to the plasma membrane in vitro, and improve glucose disposal in insulin resistant models in vivo. Here we interrogated the mechanism by which these novel compounds activate AMPK, a leading anti-diabetic drug target. BMTs did not activate AMPK directly in an allosteric manner as AMP or the Abbott compound (A-769662) does, nor did they activate AMPK by inhibiting cellular respiration like many commonly used anti-diabetic medications. BMTs increased AMPK activity in both L6 myotubes and LKB1-deficient HeLa cells by 20-35%. Incubation with the CaMKKß inhibitor, STO-609, completely attenuated this effect suggesting a key role for CaMKKß in this activation. Incubation of L6 myotubes with the calcium chelator EGTA-AM did not alter this activation suggesting that the BMT-dependent activation was Ca2+-independent. We therefore propose that CaMKKß is a key upstream kinase for BMT-induced activation of AMPK

    Obsessive-compulsive disorder and comorbid depression: the role of OCD-related and non-specific factors

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    Although comorbid depression is a predictor of poor treatment response in obsessive-compulsive disorder (OCD), there is limited understanding of factors that contribute to depression severity in OCD. The current study examines the influence of OCD-related factors (autogenous obsessions and obsessional beliefs) and non-specific factors (avoidance and anxiety) on depression severity in a sample of OCD patients. There were 56 participants with only OCD and 46 with OCD and comorbid depression. Self-report questionnaires measuring depression, OCD-related factors, and non-specific factors were completed. Although there were no significant differences between the two groups on these variables, depression severity was positively correlated with anxiety, avoidance, obsessional beliefs, and autogenous obsessions in the whole sample. When entered into a multiple regression model to predict depression severity, these factors accounted for 51% of the variance. While OCD-related factors remained significant predictors after controlling for non-specific factors, the non-specific factors made the most significant contributions to the model. Our findings suggest that in addition to dealing with autogenous obsessions, addressing anxiety and avoidance might lead to improvements in the treatment of OCD with comorbid depression

    Alternative strategies for the reduction of TDS in the western sewer system, Melbourne, Australia

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    Over the past decade shrinking freshwater supplies have forced the Victorian government to investigate alternatives sources of water for domestic and industrial uses. A significant source of alternative water is treated effluent from wastewater treatment plants. Currently the concentration of total dissolved solids (TDS) has become a major factor limiting the usefulness of effluent for irrigation from wastewater treatment facilities such as the Western Treatment Plant (WTP). This project was designed to develop alternative strategies to the current approaches being employed by Melbourne Water and City West Water to reduce TDS at the WTP. Detailed knowledge of the western sewer system was required in order to develop strategies for reduction of TDS at the WTP. This was undertaken by characterising the influent at WTP and the significant sources, domestic and industrial by applying an intensive sampling regime. The analysis of the data from the sampling investigation revealed key information required to propose TDS reduction strategies. Two strategies were presented in this study. The first strategy became apparent through the data analysis of the inputs into the WTP. It was found that diverting a proportion of the influent at times when TDS concentrations were at the highest to either a sacrificial land site or a separate lagoon system could result in significant reductions in the TDS of the recycled water. The second strategy investigated was an at-source approach. Industry was shown to have the highest contribution of TDS at the WTP. Since a significant amount of TDS comes from the pre-treatment of trade waste before discharge, an approach was investigated to eliminate neutralization prior to discharge in certain circumstances. The concept involved using the buffer capacity of the sewer to neutralise the acidic trade waste rather than using chemicals which contain high amounts of soluble inorganic ions. Two industries were chosen for case studies to investigate the feasibility of this concept. The industries chosen were located in different catchments. The first industry was located in a domestic catchment whereas the second industry was in an industrial catchment. There were two elements to this concept, the first was conducted in the laboratory and the second was conducted in the field. The laboratory component consisted of titrating both the trade waste prior to neutralisation and the receiving sewer with a strong acid and base. This demonstrated the capability of the receiving sewer flow to cope with either strong acid or base additions. The field work consisted of discharging uneutralised trade waste into the receiving sewer. The pH of the trade waste and the receiving sewer were recorded throughout the event to show the impact from the addition of the acidic trade waste. Both strategies investigated in this project were effective in demonstrating the potential of reducing TDS at the WTP

    The prediction of flanking sound transmission below the critical frequency

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    Although reliable methods exist to predict the apparent sound reduction index of heavy, homogeneous isotopic building constructions, these methods are not appropriate for use with lightweight building constructions which typically have critical frequencies in or above the frequency range of interest. Three main methods have been proposed for extending the prediction of flanking sound transmission to frequencies below the critical frequency


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