Exact series solutions of reactive transport models with general initial conditions

Exact solutions of partial differential equation models describing the transport and decay of single and coupled multispecies problems can provide insight into the fate and transport of solutes in saturated aquifers. Most previous analytical solutions are based on integral transform techniques, meaning that the initial condition is restricted in the sense that the choice of initial condition has an important impact on whether or not the inverse transform can be calculated exactly. In this work we describe and implement a technique that produces exact solutions for single and multispecies reactive transport problems with more general, smooth initial conditions. We achieve this by using a different method to invert a Laplace transform which produces a power series solution. To demonstrate the utility of this technique, we apply it to two example problems with initial conditions that cannot be solved exactly using traditional transform techniques.

A spatial-indexing model for measuring neighbourhood-level land-use and transport integration

Significant attention has been given in urban policy literature to the integration of land-use and transport planning and policies—with a view to curbing sprawling urban form and diminishing externalities associated with car-dependent travel patterns. By taking land-use and transport interaction into account, this debate mainly focuses on how a successful integration can contribute to societal well-being, providing efficient and balanced economic growth while accomplishing the goal of developing sustainable urban environments and communities. The integration is also a focal theme of contemporary urban development models, such as smart growth, liveable neighbourhoods, and new urbanism. Even though available planning policy options for ameliorating urban form and transport-related externalities have matured—owing to growing research and practice worldwide—there remains a lack of suitable evaluation models to reflect on the current status of urban form and travel problems or on the success of implemented integration policies. In this study we explore the applicability of indicator-based spatial indexing to assess land-use and transport integration at the neighbourhood level. For this, a spatial index is developed by a number of indicators compiled from international studies and trialled in Gold Coast, Queensland, Australia. The results of this modelling study reveal that it is possible to propose an effective metric to determine the success level of city plans considering their sustainability performance via composite indicator methodology. The model proved useful in demarcating areas where planning intervention is applicable, and in identifying the most suitable locations for future urban development and plan amendments. Lastly, we integrate variance-based sensitivity analysis with the spatial indexing method, and discuss the applicability of the model in other urban contexts.

Unconditionally secure disjointness tests for private datasets

We present two unconditional secure protocols for private set disjointness tests. In order to provide intuition of our protocols, we give a naive example that applies Sylvester matrices. Unfortunately, this simple construction is insecure as it reveals information about the intersection cardinality. More specifically, it discloses its lower bound. By using the Lagrange interpolation, we provide a protocol for the honest-but-curious case without revealing any additional information. Finally, we describe a protocol that is secure against malicious adversaries. In this protocol, a verification test is applied to detect misbehaving participants. Both protocols require O(1) rounds of communication. Our protocols are more efficient than the previous protocols in terms of communication and computation overhead. Unlike previous protocols whose security relies on computational assumptions, our protocols provide information theoretic security. To our knowledge, our protocols are the first ones that have been designed without a generic secure function evaluation. More important, they are the most efficient protocols for private disjointness tests in the malicious adversary case.

Producing while consuming: Social interaction around photos shared within private group

User-generated content plays a pivotal role in the current social media. The main focus, however, has been on the explicitly generated user content such as photos, videos and status updates on different social networking sites. In this paper, we explore the potential of implicitly generated user content, based on users’ online consumption behaviors. It is technically feasible to record users’ consumption behaviors on mobile devices and share that with relevant people. Mobile devices with such capabilities could enrich social interactions around the consumed content, but it may also threaten users’ privacy. To understand the potentials of this design direction we created and evaluated a low-fidelity prototype intended for photo sharing within private groups. Our prototype incorporates two design concepts, namely, FingerPrint and MoodPhotos that leverage users’ consumption history and emotional responses. In this paper, we report user values and user acceptance of this prototype from three participatory design workshops.

Efficient fuzzy matching and intersection on private datasets

At Eurocrypt’04, Freedman, Nissim and Pinkas introduced a fuzzy private matching problem. The problem is defined as follows. Given two parties, each of them having a set of vectors where each vector has T integer components, the fuzzy private matching is to securely test if each vector of one set matches any vector of another set for at least t components where t < T. In the conclusion of their paper, they asked whether it was possible to design a fuzzy private matching protocol without incurring a communication complexity with the factor (T t ) . We answer their question in the affirmative by presenting a protocol based on homomorphic encryption, combined with the novel notion of a share-hiding error-correcting secret sharing scheme, which we show how to implement with efficient decoding using interleaved Reed-Solomon codes. This scheme may be of independent interest. Our protocol is provably secure against passive adversaries, and has better efficiency than previous protocols for certain parameter values.

A Cyber-Physical System Simulator for risk-free transport studies

The article introduces a novel platform for conducting controlled and risk-free driving and traveling behavior studies, called Cyber-Physical System Simulator (CPSS). The key features of CPSS are: (1) simulation of multiuser immersive driving in a threedimensional (3D) virtual environment; (2) integration of traffic and communication simulators with human driving based on dedicated middleware; and (3) accessibility of multiuser driving simulator on popular software and hardware platforms. This combination of features allows us to easily collect large-scale data on interesting phenomena regarding the interaction between multiple user drivers, which is not possible with current single-user driving simulators. The core original contribution of this article is threefold: (1) we introduce a multiuser driving simulator based on DiVE, our original massively multiuser networked 3D virtual environment; (2) we introduce OpenV2X, a middleware for simulating vehicle-to-vehicle and vehicle to infrastructure communication; and (3) we present two experiments based on our CPSS platform. The first experiment investigates the “rubbernecking” phenomenon, where a platoon of four user drivers experiences an accident in the oncoming direction of traffic. Second, we report on a pilot study about the effectiveness of a Cooperative Intelligent Transport Systems advisory system.

The impact of corporate governance on private placements in Australia

In private placement transactions, issuing firms sell a block of securities to just a small group of investors at a discounted price. Non-participating shareholders suffer from ownership dilution and lose the opportunity to receive the discount. This thesis provides the first evidence on whether and how corporate governance can protect non-participating shareholders' interests. Results from an examination of 329 private placements issued by the top 250 Australian firms between 2002 and 2009 demonstrate that firms with higher governance quality are more likely to issue a share purchase plan (SPP) along with the private placement, thus providing greater protection to non-participating shareholders' interests.

Secure coprocessor-based private information retrieval without periodical preprocessing

Early works on Private Information Retrieval (PIR) focused on minimizing the necessary communication overhead. They seemed to achieve this goal but at the expense of query response time. To mitigate this weakness, protocols with secure coprocessors were introduced. They achieve optimal communication complexity and better online processing complexity. Unfortunately, all secure coprocessor-based PIR protocols require heavy periodical preprocessing. In this paper, we propose a new protocol, which is free from the periodical preprocessing while offering the optimal communication complexity and almost optimal online processing complexity. The proposed protocol is proven to be secure.

Efficient disjointness tests for private datasets

We present efficient protocols for private set disjointness tests. We start from an intuition of our protocols that applies Sylvester matrices. Unfortunately, this simple construction is insecure as it reveals information about the cardinality of the intersection. More specifically, it discloses its lower bound. By using the Lagrange interpolation we provide a protocol for the honest-but-curious case without revealing any additional information. Finally, we describe a protocol that is secure against malicious adversaries. The protocol applies a verification test to detect misbehaving participants. Both protocols require O(1) rounds of communication. Our protocols are more efficient than the previous protocols in terms of communication and computation overhead. Unlike previous protocols whose security relies on computational assumptions, our protocols provide information theoretic security. To our knowledge, our protocols are first ones that have been designed without a generic secure function evaluation. More importantly, they are the most efficient protocols for private disjointness tests for the malicious adversary case.

Distributed private matching and set operations

Motivated by the need of private set operations in a distributed environment, we extend the two-party private matching problem proposed by Freedman, Nissim and Pinkas (FNP) at Eurocrypt’04 to the distributed setting. By using a secret sharing scheme, we provide a distributed solution of the FNP private matching called the distributed private matching. In our distributed private matching scheme, we use a polynomial to represent one party’s dataset as in FNP and then distribute the polynomial to multiple servers. We extend our solution to the distributed set intersection and the cardinality of the intersection, and further we show how to apply the distributed private matching in order to compute distributed subset relation. Our work extends the primitives of private matching and set intersection by Freedman et al. Our distributed construction might be of great value when the dataset is outsourced and its privacy is the main concern. In such cases, our distributed solutions keep the utility of those set operations while the dataset privacy is not compromised. Comparing with previous works, we achieve a more efficient solution in terms of computation. All protocols constructed in this paper are provably secure against a semi-honest adversary under the Decisional Diffie-Hellman assumption.

When should private property rights give way to the public interest?

Since Queensland Wire Industries Pty Ltd v Broken Hill Pty Co Ltd (1989) 167 CLR 177 it has been recognised that corporations with substantial market power are subject to special responsibilities and restraints that corporations without market power are not. In NT Power Generation Pty Ltd v Power and Water Authority (2004) 219 CLR 90 McHugh A-CJ, Gummow, Callinan and Heydon JJ in their joint reasons stated (at [76]), that s 46 of the Competition and Consumer Act 2010 (Cth) (CCA) can operate not only to prevent firms with substantial market power from doing prohibited things, but also compel them positively to do things they do not want to do. Their Honours also stated (at [126]) that the proposition that a private property owner who declines to permit competitors to use the property is immune from s 46 is “intrinsically unsound”. However, the circumstances in which a firm with substantial power must accommodate competitors, and private property rights give way to the public interest are uncertain. The purpose of this Note is to consider recent developments in two areas of the CCA where the law requires private property rights to give way to the public interest. The first part of the Note considers two recent cases which clarify the circumstances in which s 46 of the CCA can be used to compel a firm with substantial market power to accommodate a competitor and allow the competitor to make use of private property rights in the public interest. Secondly, on 12 February 2014 the Minister for Small Business, the Hon Bruce Billson,released the Productivity Commission’s Final Report, on the National Access Regime in Pt IIIA of the CCA (National Access Regime, Inquiry Report No 66, Canberra). Pt IIIA provides for the processes by which third parties may obtain access to infrastructure owned by others in the public interest. The Report recommends that Pt IIIA be retained but makes a number of suggestions for its reform, some of which will be briefly considered.

Taxation determinations as de facto regulation : private equity exits in Australia

The Australian Taxation Office (AT)) attempted to challenge both the private equity fund reliance on double tax agreements and the assertion that profits were capital in nature in its dispute with private equity group TPG. Failure to resolve the dispute resulted in the ATO issuing two taxation determinations: TD 2010/20 which states that the general anti-avoidance provisions can apply to arrangements designed to alter the intended effect of Australia's international tax agreements net; and TD 2010/21 which states that the profits on the sale of shares in a company group acquired in a leveraged buyout is assessable income. The purpose of this article is to determine the effectiveness of the administrative rulings regime as a regulatory strategy. This article, by using the TPG-Myer scenario and subsequent tax determinations as a case study, collects qualitative data which is then analysed (and triangulated) using tonal and thematic analysis. Contemporaneous commentary of private equity stakeholders, tax professionals, and media observations are analysed and evaluated within a framework of responsive regulation and utilising the current ATO compliance model. Contrary to the stated purpose of the ATO rulings regime to alleviate complexities in Australian taxation law and provide certainty to taxpayers, and despite the de facto law status afforded these rulings, this study found that the majority of private equity stakeholders and their advisors perceived that greater uncertainty was created by the two determinations. Thus, this study found that in the context of private equity fund investors, a responsive regulation measure in the form of taxation determinations was not effective.

A design approach to the study of people's experiences with technologies in the context of public transport

Relevant to the study of people’s attitudes towards public transport use is the consideration to the role of technology as part of the travel experience. Technologies aim to enhance daily tasks but tend to change the way people interact with products and can be perceived as difficult to use. This is critical in the context of “public use” where products and services are to be used by the population at large: adults, children, elderly, people with disabilities, and tourists. From different perspectives, the topic of users and the use of technologies have been studied in the social sciences and human computer interaction fields; however, earlier approaches fail to address the ways in which experiential knowledge informs people’s interactions with products and technologies, and how such information could guide the design of future technologies. This paper describes a pilot study, part of a larger ongoing exploratory research that investigates people’s experiences with infrastructure, systems, and technologies in the context of public transport. The methodological approach included focus groups, field observations, and retrospective verbal reports. At this stage, the study found that four context led factors were the primary source of reference informing participants’ actions and interactions; they are: (i) context >> experience, (ii) context >> interface, (iii) context >> knowledge, (iv) context >> emotion.

Critical review of time-dependent shortest path algorithms: A multimodal trip planner perspective

A multimodal trip planner that produces optimal journeys involving both public transport and private vehicle legs has to solve a number of shortest path problems, both on the road network and the public transport network. The algorithms that are used to solve these shortest path problems have been researched since the late 1950s. However, in order to provide accurate journey plans that can be trusted by the user, the variability of travel times caused by traffic congestion must be taken into consideration. This requires the use of more sophisticated time-dependent shortest path algorithms, which have only been researched in depth over the last two decades, from the mid-1990s. This paper will review and compare nine algorithms that have been proposed in the literature, discussing the advantages and disadvantages of each algorithm on the basis of five important criteria that must be considered when choosing one or more of them to implement in a multimodal trip planner.