Visualisation of complex flows using texture-based techniques

Complex flow datasets are often difficult to represent in detail using traditional vector visualisation techniques such as arrow plots and streamlines. This is particularly true when the flow regime changes in time. Texture-based techniques, which are based on the advection of dense textures, are novel techniques for visualising such flows (i.e., complex dynamics and time-dependent). In this paper, we review two popular texture-based techniques and their application to flow datasets sourced from real research projects. The texture-based techniques investigated were Line Integral Convolution (LIC), and Image-Based Flow Visualisation (IBFV). We evaluated these techniques and in this paper report on their visualisation effectiveness (when compared with traditional techniques), their ease of implementation, and their computational overhead.

Visualisation of complex flows using texture-based techniques

Detailed representations of complex flow datasets are often difficult to generate using traditional vector visualisation techniques such as arrow plots and streamlines. This is particularly true when the flow regime changes in time. Texture-based techniques, which are based on the advection of dense textures, are novel techniques for visualising such flows. We review two popular texture based techniques and their application to flow datasets sourced from active research projects. The techniques investigated were Line integral convolution (LIC) [1], and Image based flow visualisation (IBFV) [18]. We evaluated these and report on their effectiveness from a visualisation perspective. We also report on their ease of implementation and computational overheads.

Dynamic Bayesian network inferencing for non-homogeneous complex systems

Dynamic Bayesian Networks (DBNs) provide a versatile platform for predicting and analysing the behaviour of complex systems. As such, they are well suited to the prediction of complex ecosystem population trajectories under anthropogenic disturbances such as the dredging of marine seagrass ecosystems. However, DBNs assume a homogeneous Markov chain whereas a key characteristics of complex ecosystems is the presence of feedback loops, path dependencies and regime changes whereby the behaviour of the system can vary based on past states. This paper develops a method based on the small world structure of complex systems networks to modularise a non-homogeneous DBN and enable the computation of posterior marginal probabilities given evidence in forwards inference. It also provides an approach for an approximate solution for backwards inference as convergence is not guaranteed for a path dependent system. When applied to the seagrass dredging problem, the incorporation of path dependency can implement conditional absorption and allows release from the zero state in line with environmental and ecological observations. As dredging has a marked global impact on seagrass and other marine ecosystems of high environmental and economic value, using such a complex systems model to develop practical ways to meet the needs of conservation and industry through enhancing resistance and/or recovery is of paramount importance.

Flow regime transition criteria for two-phase flow at reduced gravity conditions

Flow regime transition criteria are of practical importance for two-phase flow analyses at reduced gravity conditions. Here, flow regime transition criteria which take the friction pressure loss effect into account were studied in detail. Criteria at reduced gravity conditions were developed by extending an existing model with various experimental datasets taken at microgravity conditions showed satisfactory agreement. Sample computations of the model were performed at various gravity conditions, such as 0.196, 1.62, 3.71, and 9.81 m/s2 corresponding to micro-gravity and lunar, Martian and Earth surface gravity, respectively. It was found that the effect of gravity on bubbly-slug and slug-annular (churn) transitions in a two-phase flow system was more pronounced at low liquid flow conditions, whereas the gravity effect could be ignored at high mixture volumetric flux conditions. While for the annular flow transitions due to flow reversal and onset of dropset entrainment, higher superficial gas velocity was obtained at higher gravity level.

Equity for taxpayers within Australia’s retirement savings regime : a dissenting opinion

This article asks the question whether Australia’s retirement savings regime, specifically the superannuation component and the attached taxation concessions, is a regime which is equitable to all taxpayers. In a dissenting opinion, it is argued that the current regime, along with the changes proposed by the Federal Government in its response to the Henry Review, does not result in a retirement savings regime which benefits all taxpayers equally. As such, it is suggested that the only way to ensure an equitable regime is to incorporate a gender perspective into public finance analysis to determine how the retirement savings policies affect women and men differently. In doing so, a specific tax policy which provides for additional, fiscally significant concessions for taxpayers who do not fit the criteria of a ‘normal’ taxpayer, that is a taxpayer working as an employee in a full time position for an uninterrupted 35 years, should be incorporated into Australia’s current fiscal policy.

The inherent international tax regime and its constraints on Australia's sovereignty

On 1 November 2011 the Minister for Financial Services and Superannuation, the Honourable Bill Shorten MP, announced that Australia would be undertaking a reform of the ‘transfer pricing rules in the income tax law and Australia’s future tax treaties to bring them into line with international best practice, improving the integrity and efficiency of the tax system.’ Mr Shorten stated that the reason for the reform was that ‘recent court decisions suggest our existing transfer pricing rules may be interpreted in a way that is out-of-kilter with international norms.’ Further, he stated that ‘the Government has asked the Treasury to review how the transfer pricing rules can be improved, including but not limited to how to be more in line with international best practice.’ He urged all interested parties to participate in this consultation process. On 16 March 2012, an Exposure Draft and accompanying Explanatory Memorandum outlining the proposed amendments to implement the first stage of the transfer pricing reforms were released. Within the proposed changes is the explicit embedding of the use of the OECD’s Model Tax Convention on Income and on Capital and Transfer Pricing Guidelines for Multinational Enterprises and Tax Administrations to help determine the arm’s length price. Does this mean that Australia engages in an international tax regime?

The inherent international tax regime and its constraints on Australia's sovereignty

Neither an international tax, nor an international taxing body exists. Rather, there are domestic taxing rules adopted by jurisdictions which, coupled with double tax treaties, apply to cross-border transactions and international taxation issues. International bodies such as the OECD and UN, which provide guidance on tax issues, often steer and supplement these domestic adoptions but have no binding international taxing powers. These pragmatic realities, together with the specific use of the word ‘regime’ within the tax community, lead many to argue that an international tax regime does not exist. However, an international tax regime should be defined no differently to any other area of international law and when we step outside the confines of tax law to consider the definition of a ‘regime’ within international relations it is possible to demonstrate that such a regime is very real. The first part of this article, by defining an international tax regime in a broader and more traditional context, also outlining both the tax policy and principles which frame that regime, reveals its existence. Once it is accepted that an international tax regime exists, it is possible to consider its adoption by jurisdictions and subsequent constraints it places on them. Using the proposed changes to transfer pricing laws as the impetus for assessing Australia’s adoption of the international tax regime, the constraints on sovereignty are assessed through a taxonomy of the level adoption. This reveals the subsequent constraints which flow from the broad acceptance of an international tax regime through to the specific adoption of technical detail. By undertaking this analysis, the second part of this article demonstrates that Australia has inherently adopted an international tax regime, with a move towards explicit adoption and a clear embedding of its principles within the domestic tax legislation.

New regime for property agents and residential property sales in Queensland : Property Occupations Act 2014

This article examines the new Property Occupations Act 2014 (POA) and relevant provisions of the Agents Financial Administration Act 2014 (AFAA) and the impacts for property practitioners. The Acts are due to commence later in 2014 once regulations and relevant forms are drafted. Coinciding with the commencement of the Acts further versions of the REIQ Houses and Land Contract and REIQ Community Title Contract will also be released. The POA introduces changes for licencing of real estate agents, property developers and resident letting agents as well as significant changes for the contract formation process. The AFAA includes the trust account and claim fund provisions of PAMDA, which avoids duplication of these provisions across each of the industry-specific Bills. The most significant change is to the process for making a claim against the fund for the conduct of property agents.

Ecosystem management along ephemeral rivers: Trading off socio-economic water supply and vegetation conservation under flood regime uncertainty

In ecosystems driven by water availability, plant community dynamics depend on complex interactions between vegetation, hydrology, and human water resources use. Along ephemeral rivers—where water availability is erratic—vegetation and people are particularly vulnerable to changes in each other's water use. Sensible management requires that water supply be maintained for people, while preserving ecosystem health. Meeting such requirements is challenging because of the unpredictable water availability. We applied information gap decision theory to an ecohydrological system model of the Kuiseb River environment in Namibia. Our aim was to identify the robustness of ecosystem and water management strategies to uncertainties in future flood regimes along ephemeral rivers. We evaluated the trade-offs between alternative performance criteria and their robustness to uncertainty to account for both (i) human demands for water supply and (ii) reducing the risk of species extinction caused by water mining. Increasing uncertainty of flood regime parameters reduced the performance under both objectives. Remarkably, the ecological objective (species coexistence) was more sensitive to uncertainty than the water supply objective. However, within each objective, the relative performance of different management strategies was insensitive to uncertainty. The ‘best’ management strategy was one that is tuned to the competitive species interactions in the Kuiseb environment. It regulates the biomass of the strongest competitor and, thus, at the same time decreases transpiration, thereby increasing groundwater storage and reducing pressure on less dominant species. This robust mutually acceptable strategy enables species persistence without markedly reducing the water supply for humans. This study emphasises the utility of ecohydrological models for resource management of water-controlled ecosystems. Although trade-offs were identified between alternative performance criteria and their robustness to uncertain future flood regimes, management strategies were identified that help to secure an ecologically sustainable water supply.