The renormalization group and the implicit function theorem for amplitude equations

This article lays down the foundations of the renormalization group (RG) approach for differential equations characterized by multiple scales. The renormalization of constants through an elimination process and the subsequent derivation of the amplitude equation [Chen, Phys. Rev. E 54, 376 (1996)] are given a rigorous but not abstract mathematical form whose justification is based on the implicit function theorem. Developing the theoretical framework that underlies the RG approach leads to a systematization of the renormalization process and to the derivation of explicit closed-form expressions for the amplitude equations that can be carried out with symbolic computation for both linear and nonlinear scalar differential equations and first order systems but independently of their particular forms. Certain nonlinear singular perturbation problems are considered that illustrate the formalism and recover well-known results from the literature as special cases. © 2008 American Institute of Physics.

Secular series and renormalization group for amplitude equations

We have developed a technique that circumvents the process of elimination of secular terms and reproduces the uniformly valid approximations, amplitude equations, and first integrals. The technique is based on a rearrangement of secular terms and their grouping into the secular series that multiplies the constants of the asymptotic expansion. We illustrate the technique by deriving amplitude equations for standard nonlinear oscillator and boundary-layer problems. © 2008 The American Physical Society.

Renormalization group interpretation of the Born and Rytov approximations

In this paper the method of renormalization group (RG) [Phys. Rev. E 54, 376 (1996)] is related to the well-known approximations of Rytov and Born used in wave propagation in deterministic and random media. Certain problems in linear and nonlinear media are examined from the viewpoint of RG and compared with the literature on Born and Rytov approximations. It is found that the Rytov approximation forms a special case of the asymptotic expansion generated by the RG, and as such it gives a superior approximation to the exact solution compared with its Born counterpart. Analogous conclusions are reached for nonlinear equations with an intensity-dependent index of refraction where the RG recovers the exact solution. © 2008 Optical Society of America.

The World Cup that was : a look back through social media

On Sunday, Germany held the World Cup aloft after scoring a goal in extra time. Somewhat surprisingly, the final wasn’t the most tweeted event of the 2014 tournament: that title went to Germany’s demolition of Brazil in its semi-final four days earlier, which ended up being the most tweeted sporting event in history. Let’s take a look back at some of the bigger stories of the World Cup from social media, as well as the prominence of the event in Europe...

Standards that we can 'own' : Threshold Learning Outcomes for Journalism, Public Relations, and Media & Communication Studies

This paper outlines the progress by the JoMeC (Journalism, Media & Communication) Network in developing TLO (Threshold Learning Outcome) statements for Bachelor-level university programs in the disciplines of Journalism, Public Relations and Media & Communications Studies. The paper presents the finalised TLO statement for Journalism, and outlines moves to engage discipline-based groups to further develop preliminary TLOs for Public Relations and Media & Communication Studies. The JoMeC Network was formed in 2011, in response to requirements that from 2014 all degrees and qualifications at Australian universities would be able to demonstrate that they comply with the threshold learning standards set by the Australian Qualifications Framework (AQF). The AQF’s threshold standards define the minimum types and levels of knowledge, skills and capabilities that a student must demonstrate in order to graduate. The Tertiary Education Quality and Standards Agency (TEQSA) will use the AQF’s threshold standards as a key tool in recording and assessing the performance of higher educational institutions, and determining whether they should be registered as Australian Higher Education Providers under the Higher Education Standards Framework. The Office of Learning & Teaching (OLT) places the onus on discipline communities to collaborate in order to develop and ‘own’ the threshold learning standards that can be considered the minimum learning outcomes of university-level programs in that field. With the support of an OLT Grant, the JoMeC Network’s prime goal has been to develop three sets of discipline-specific TLOs – one each for the Journalism, Public Relations, and Media & Communications Studies disciplines. This paper describes the processes of research, consultation, drafting and ongoing revision of the TLO for Journalism. It outlines the processes that the JoMeC Network has taken in developing a preliminary TLO draft to initiate discussion of Public Relations and Media & Communication Studies. The JoMeC Network plans to hand management of further development of these TLOs to scholars within the discipline who will engage with academics and other stakeholders to develop statements that the respective disciplines can embrace and ‘own’.

A non-malleable group key exchange protocol robust against active insiders

In this paper we make progress towards solving an open problem posed by Katz and Yung at CRYPTO 2003. We propose the first protocol for key exchange among n ≥2k+1 parties which simultaneously achieves all of the following properties: 1. Key Privacy (including forward security) against active attacks by group outsiders, 2. Non-malleability — meaning in particular that no subset of up to k corrupted group insiders can ‘fix’ the agreed key to a desired value, and 3. Robustness against denial of service attacks by up to k corrupted group insiders. Our insider security properties above are achieved assuming the availability of a reliable broadcast channel.

On secure multi-party computation in black-box groups

We study the natural problem of secure n-party computation (in the passive, computationally unbounded attack model) of the n-product function f G (x 1,...,x n ) = x 1 ·x 2 ⋯ x n in an arbitrary finite group (G,·), where the input of party P i is x i  ∈ G for i = 1,...,n. For flexibility, we are interested in protocols for f G which require only black-box access to the group G (i.e. the only computations performed by players in the protocol are a group operation, a group inverse, or sampling a uniformly random group element). Our results are as follows. First, on the negative side, we show that if (G,·) is non-abelian and n ≥ 4, then no ⌈n/2⌉-private protocol for computing f G exists. Second, on the positive side, we initiate an approach for construction of black-box protocols for f G based on k-of-k threshold secret sharing schemes, which are efficiently implementable over any black-box group G. We reduce the problem of constructing such protocols to a combinatorial colouring problem in planar graphs. We then give two constructions for such graph colourings. Our first colouring construction gives a protocol with optimal collusion resistance t < n/2, but has exponential communication complexity O(n*2t+1^2/t) group elements (this construction easily extends to general adversary structures). Our second probabilistic colouring construction gives a protocol with (close to optimal) collusion resistance t < n/μ for a graph-related constant μ ≤ 2.948, and has efficient communication complexity O(n*t^2) group elements. Furthermore, we believe that our results can be improved by further study of the associated combinatorial problems.

Securing multicast groups in ad hoc networks

We propose a reliable and ubiquitous group key distribution scheme that is suitable for ad hoc networks. The scheme has self-initialisation and self-securing features. The former feature allows a cooperation of an arbitrary number of nodes to initialise the system, and it also allows node admission to be performed in a decentralised fashion. The latter feature allows a group member to determine the group key remotely while maintaining the system security. We also consider a decentralised solution of establishing secure point-to-point communication. The solution allows a new node to establish a secure channel with every existing node if it has pre-existing secure channels with a threshold number of the existing nodes.

iPads in the Early Years : Developing Literacy and Creativity

Digital devices like smart phones and tablet computers are becoming commonplace in young children’s lives for play, entertainment, learning and communication. Recently, there has been a great deal of focus on the educational potential of devices like iPads in both formal and informal educational settings. There is now an abundance of educational ‘apps’ available to children, parents, and kindergarten and pre-school teachers that claim to enhance children’s early literacy and numeracy development and creativity. To date, though, there has been very little formal investigation of the educational potential of these devices. This book discusses the impact on children’s learning when iPads were introduced in three very different kindergartens in Brisbane, Australia. Chapters outline how researchers worked with pre-school teachers and parents to explore how iPads can assist with letter and word recognition, the development of oral literacy and talk around play. The book also considers the possibilities for using iPads for creativity and arts education through photography, storytelling, drawing, music creation and audio recording.

Digital Media Literacies in the Early Years

This chapter addresses children’s development of digital media literacies with iPads in preschool settings. The authors argue that children living in post-industrial societies participate in ‘transmedia’ experiences that call for new understandings of media literacy that recognise children’s ability to successfully participate in complex media ecologies. The chapter outlines a model for digital media literacies that includes the application of digital materials and media concepts through the processes of media production and media analysis. This model is then used as a framework to interpret children’s media production work across the preschools in our project.

Networking iPads into Preschool Spaces

This chapter explores preschools as networked spaces into which iPads were introduced, which involved the mediation of complex relationships between children and adults, physical and virtual technology and other materials like toys, play spaces, art materials and books. The chapter aims to explain how these human and non-human ‘actors’ come to coexist and lead to the development of literacy and creativity in specific ways. This approach particularly draws attention to specific challenges faced by the teachers as they negotiated a range of complex demands and obstacles to make the iPads available to the children for play and learning.

Detection of sinkhole attack in wireless sensor networks

Generally wireless sensor networks rely of many-to-one communication approach for data gathering. This approach is extremely susceptible to sinkhole attack, where an intruder attracts surrounding nodes with unfaithful routing information, and subsequently presents selective forwarding or change the data that carry through it. A sinkhole attack causes an important threat to sensor networks and it should be considered that the sensor nodes are mostly spread out in open areas and of weak computation and battery power. In order to detect the intruder in a sinkhole attack this paper suggests an algorithm which firstly finds a group of suspected nodes by analyzing the consistency of data. Then, the intruder is recognized efficiently in the group by checking the network flow information. The proposed algorithm's performance has been evaluated by using numerical analysis and simulations. Therefore, accuracy and efficiency of algorithm would be verified.

Drawing and writing on the screen

This chapter focuses on the physicality of the iPad as an object, and how that physicality affects the interactions children have with the device generally, and the apps specifically. Thinking about the physicality of the iPad is important because the materials, size, weight and appearance make the iPad quite unlike most other toys and equipment in the kindergarten space. Most strikingly, this physicality does not ‘represent’ the virtual vast dimensions of the iPad brought about through the diverse functions and contents of the apps contained in it. While the iPad is small enough and functional enough to be easily handled and operated even by young children, it is capable of performing highly complex, highly technological tasks that take it beyond its diminutive dimensions. This virtual-actual contrast is interesting to consider in relation to the other resources more commonly found in a kindergarten space. While objects such as toys, bricks, building materials often do prompt the child to imagine and invent beyond the physical boundaries of the toy, they not have the same types of virtual-actual contrasts of a digital device such as the iPad. How then, might children be drawn to the iPad because of its physical, technological and virtual difference? Particularly, how might this virtual-actual difference impact on the physical skills associated with writing and drawing: skills usually learnt through the use of a pencil and paper? While the research project did not set out to compare how digital and paper-based resources affect writing and drawing skills there was great interest to see how young children negotiated drawing and writing on the shiny glass surface of the iPad.

Visual arts learning with iPads

In this chapter Knight & Dooley discuss arts learning and issues of educational authenticity via children’s engagement with iPads (O’Mara & Laidlaw 2011; Shifflet, Toledo & Mattoon 2012). The chapter begins by considering common perceptions about art and how these popular beliefs and conditions affect and influence how children’s art is defined and valorized. The art produced by children using iPads is then discussed through key observations and reflections, and the chapter concludes with some recommendations when selecting apps for making art.

Educating for the creative economy in emerging countries

In 1972, the United Nations (UN) Conference on the Human Environment expressed a growing realization that economic and social progress needed to be balanced with a concern for the environment and the stewardship of natural resources. The hard-to-grasp concept of "sustainable development" was first defined as "development that meets the needs of the present without compromising the ability of future generations to meet their needs" (World Commission on Environment and Development [WESDJ, 1987, p. 43). This definition contains two concepts: first, "human needs," with priority given to the world's poor, and, second, the environment's limits for meeting the state of technological and social organization (WESD, 1987, p. 43). At the 2002 World Summit on Sustainable Development (UN, 2002a), the focus on environmental protection broadened to encompass social justice and the fight against poverty as key principles of development that is sustainable. Three interdependent and mutually reinforcing "pillars" were recognized: economic development, social development, and environmental protection. These pillars must be established at local, national, and global levels. The complexity and interrelationship of critical issues such as poverty, wasteful consumption, urban decay, population growth, gender inequality, health, conflict, and the violation of human rights are addressed in all three pillars (Pigozzi, 2003, p. 3). Following the concept of sustainable development, we argue that the challenge for developing countries in contemporary society is to meet the very real need for economic development and opportunities for income generation, while avoiding the unintended and unwanted consequences of economic development and globalization. These consequences include social exclusion, loss of cultural heritage, and environmental and ecological problems.