Propagation of low power low divergence Gaussian fields in unbiased self-defocusing photorefractive media and their interactions

Many optical networks are limited in speed and processing capability due to the necessity for the optical signal to be converted to an electrical signal and back again. In addition, electronically manipulated interconnects in an otherwise optical network lead to overly complicated systems. Optical spatial solitons are optical beams that propagate without spatial divergence. They are capable of phase dependent interactions, and have therefore been extensively researched as suitable all optical interconnects for over 20 years. However, they require additional external components, initially high voltage power sources were required, several years later, high power background illumination had replaced the high voltage. However, these additional components have always remained as the greatest hurdle in realising the applications of the interactions of spatial optical solitons as all optical interconnects. Recently however, self-focusing was observed in an otherwise self-defocusing photorefractive crystal. This observation raises the possibility of the formation of soliton-like fields in unbiased self-defocusing media, without the need for an applied electrical field or background illumination. This thesis will present an examination of the possibility of the formation of soliton-like low divergence fields in unbiased self-defocusing photorefractive media. The optimal incident beam and photorefractive media parameters for the formation of these fields will be presented, together with an analytical and numerical study of the effect of these parameters. In addition, preliminary examination of the interactions of two of these fields will be presented. In order to complete an analytical examination of the field propagating through the photorefractive medium, the spatial profile of the beam after propagation through the medium was determined. For a low power solution, it was found that an incident Gaussian field maintains its Gaussian profile as it propagates. This allowed the beam at all times to be described by an individual complex beam parameter, while also allowing simple analytical solutions to the appropriate wave equation. An analytical model was developed to describe the effect of the photorefractive medium on the Gaussian beam. Using this model, expressions for the required intensity dependent change in both the real and imaginary components of the refractive index were found. Numerical investigation showed that under certain conditions, a low powered Gaussian field could propagate in self-defocusing photorefractive media with divergence of approximately 0.1 % per metre. An investigation into the parameters of a Ce:BaTiO3 crystal showed that the intensity dependent absorption is wavelength dependent, and can in fact transition to intensity dependent transparency. Thus, with careful wavelength selection, the required intensity dependent change in both the real and imaginary components of the refractive index for the formation of a low divergence Gaussian field are physically realisable. A theoretical model incorporating the dependence of the change in real and imaginary components of the refractive index on propagation distance was developed. Analytical and numerical results from this model are congruent with the results from the previous model, showing low divergence fields with divergence less than 0.003 % over the propagation length of the photorefractive medium. In addition, this approach also confirmed the previously mentioned self-focusing effect of the self-defocusing media, and provided an analogy to a negative index GRIN lens with an intensity dependent focal length. Experimental results supported the findings of the numerical analysis. Two low divergence fields were found to possess the ability to interact in a Ce:BaTiO3 crystal in a soliton-like fashion. The strength of these interactions was found to be dependent on the degree of divergence of the individual beams. This research found that low-divergence fields are possible in unbiased self-defocusing photorefractive media, and that soliton-like interactions between two of these fields are possible. However, in order for these types of fields to be used in future all optical interconnects, the manipulation of these interactions, together with the ability for these fields to guide a second beam at a different wavelength, must be investigated.

The internet and the changing global media environment

This chapter describes current trends in the global media environment, with a focus on their implications for the management of public agendas and political processes. It assesses the extent to which trends such as the growth of the blogosphere, "citizen journalism," and other forms if user-generated content, have complicated and problematized news and agenda management as engaged in by both media and political elites. It argues that, in large part due to the rise of the internet and the proliferation if online producers of information and commentary, alongside 24-hour news channels such as CNN and Al Jazeera, political and social actors today face a much more complex, chaotic communication environment than ever bifore, an environment characterized as one of cultural chaos. Having outlined the roots of this trend in the emergence of an expanded, globalized public sphere, the chapter goes on to ask if elite control over the political agenda has been eroded, and if it has, what the consequences for governmmt and the exercise if power might be. Can authoritarian regimes in China, the Middle East, and elsewhere survive the onset if internet-fueled global journalism, for example? In a political environment where public opinion is driven and buffeted by news coverage if unprecedented speed and volume, can democratic governments retain sufficient control over decision- and policy-making processes to enable competent social administration al'ld political management? Can the citizens of contemporary democracies use the emerging media environment to enhance elite accountability and strengthen the democratic process? The chapter concludes that the changing global media environment has the potmtial to strengthen democratic processes, though there is no sil'lgle template for the impact of the internet and other new media on specific countries.

‘Show Me Your Wiki and I’ll Show you Mine’: Using Online Interactive Media to Improve Academic Writing and Research in a Public Health Under-Graduate Cohort

The number of Internet users in Australia has been steadily increasing, with over 10.9 million people currently subscribed to an internet provider (ABS, 2011). Over the past year, the most avid users of the Internet were 15 – 24 year olds, with approximately 95% accessing the internet on a regular basis (ABS, Social Trends, 2011). While the internet has been described as fundamental to higher education students, social and leisure internet tools are also increasingly being used by these students to generate and maintain their social and professional networks and interactions (Duffy & Bruns 2006). Rapid technological advancements have enabled greater and faster access to information for learning and education (Hemmi et al, 2009; Glassman and Kang, 2011). As such, we sought to integrate interactive, online social media into the assessment profile of a Public Health undergraduate cohort at the Queensland University of Technology (QUT). The aim of this exercise was to engage students to both develop and showcase their research on a range of complex, contemporary health issues within the online forum of Wikispaces (http://www.wikispaces.com/) for review and critique by their peers. We applied Bandura’s Social Learning Theory (SLT) to analyse the interactive processes from which students developed deeper and more sustained learning, and via which their overall academic writing standards were raised. This paper outlines the assessment task, and the students’ feedback on their learning outcomes in relation to the Attentional, Retentional, Motor Reproduction, and Motivational Processes outlined by Bandura in SLT. We conceptualise the findings in a theoretical model, and discuss the implications for this approach within the broader tertiary environment.

Framing sexual harassment through media representations

This article examines mainstream news media texts reporting sexual harassment in four industrialized countries. The study first identifies the aspects of sexual harassment cases considered newsworthy by asking how the media texts characterize such cases. Second, the study illuminates the discourses evident in these texts, which are theorized as a mode by which understandings of workplace gender (in)equality shape, and are shaped by, individuals, organizations and the community. The analysis reveals that the media most frequently reports “classic” sexual harassment and emphasizes scandalous allegations and overtly sexualized conduct. The hegemony of a discourse of sexual harassment as an individualized problem of inappropriate employee behavior is also evident. By contrast, discourses presenting sexual harassment as a systemic issue, or as symptomatic of broader gender inequality, are less frequent. We argue that these media representations limit opportunities to frame sexual harassment as dynamic, complex, and part of the practice of gendering in and beyond organizational boundaries.

Masturbation and the media

This paper explores the important role the media play in informing young people about masturbation. A pilot study of focus groups with twenty-two young Australians, aged between 14-16 explored what they know about sex and sexuality, and where they have found that knowledge. This paper reports on their knowledge about masturbation. Although researchers agree that masturbation can be a positive part of healthy sexual development, most young people reported that they received very little positive information about it from their parents or in formal sex education in school. These young people’s discussions around this topic were largely ambivalent, but also highly complex due to the varying levels and types of information that they receive. In this context the media play a vital role in providing information about masturbation through books and magazines for young women, and television comedies for young men.

Changing tastes in food media : a study of recipe sharing traditions in the food blogging community

Food is inherently cultural yet traditionally overlooked in many disciplines as a topic worthy of serious investigation. This thesis investigates how food, as a topic of interest, is thriving in an online environment through recipe sharing on food blogs. It applies an ethnographic approach to online community studies, providing a rich description of the food blogging community. The thesis demonstrates how the food blogging can be seen as a community. Through a case study focusing on a one recipe shared across many blogs, it also examines the community in action. As the community has grown, it has become more complex, structured and diverse. The thesis examines its evolution and the response of food-related media and other industries to food blogging. The nature of the food blogging community reflects the cultural and social nature of food and the ongoing evolution of recipe sharing through food-related media. Food blogs provide an insight into the eating habits of ‘ordinary’ people, in a more broad-based manner than traditional food-related media such as cookbooks. Beyond this, food blogs are part of wider cultural trends towards DIY, and provide a useful example of the ongoing transformation of food-related media, food culture, and indeed, culture more broadly.

Graphyne and graphdiyne : versatile catalysts for dehydrogenation of light metal complex hydrides

The interaction between new two-dimensional carbon allotropes, i.e. graphyne (GP) and graphdiyne (GD), and light metal complex hydrides LiAlH4, LiBH4, and NaAlH4 was studied using density functional theory (DFT) incorporating long range van der Waals dispersion correction. The light metal complex hydrides show much stronger interaction with GP and GP than that with fullerene due to the well defined pore structure. Such strong interactions greatly affect the degree of charge donation from the alkali metal atom to AlH4 or BH4, consequently destabilizing the Al-H or B-H bonds. Compared to the isolated light metal complex hydride, the presence of GP or GD can lead to a significant reduction of the hydrogen removal energy. Most interestingly, the hydrogen removal energies for LiBHx on GP and with GD are found to be lowered at all the stages (x from 4 to 1) whereas the H-removal energy in the third stage is increased for LiBH4 on fullerene. In addition, the presence of uniformly distributed pores on GP and GD is expected to facilitate the dehydrogenation of light metal complex hydrides. The present results highlight new interesting materials to catalyze light metal complex hydrides for potential application as media for hydrogen storage. Since GD has been successfully synthesized in a recent experiment, we hope the present work will stimulate further experimental investigations in this direction.

Convergent media policy : the Australian case

This chapter considers the implications of convergence for media policy from three perspectives. First, it discusses what have been the traditional concerns of media policy, and the challenges it faces, from the perspectives of public interest theories, economic capture theories, and capitalist state theories. Second, it looks at what media convergence involves, and some of the dilemmas arising from convergent media policy including: (1) determining who is a media company; (2) regulatory parity between ‘old’ and ‘new’ media; (3) treatment of similar media content across different platforms; (4) distinguishing ‘big media’ from user-created content, and: (5) maintaining a distinction between media regulation and censorship of personal communication. Finally, it discusses attempts to reform media policy in light of these changes, including Australian media policy reports from 2011-12 including the Convergence Review, the Finkelstein Review of News Media, and the Australian Law Reform Commission’s National Classification Scheme Review. It concludes by arguing that ‘public interest’ approaches to media policy continue to have validity, even as they grapple with the complex question of how to understand the concept of influence in a convergent media environment.

Complex Modelling in the Primary and Middle School Years : An Interdisciplinary Approach

The world’s increasing complexity, competitiveness, interconnectivity, and dependence on technology generate new challenges for nations and individuals that cannot be met by continuing education as usual. With the proliferation of complex systems have come new technologies for communication, collaboration, and conceptualisation. These technologies have led to signifi cant changes in the forms of mathematical and scientifi c thinking required beyond the classroom. Modelling, in its various forms, can develop and broaden students’ mathematical and scientific thinking beyond the standard curriculum. This chapter first considers future competencies in the mathematical sciences within an increasingly complex world. Consideration is then given to interdisciplinary problem solving and models and modelling, as one means of addressing these competencies. Illustrative case studies involving complex, interdisciplinary modelling activities in Years 1 and 7 are presented.

From ‘broadcast yourself’ to ‘follow your interests’ : making over social media

In this article I briefly trace the complex and incremental but significant ways that social media platforms have been transformed since the ‘Web 2.0’ moment of the early 2000s, identifying some common trajectories across several platforms, and discussing their consequences for how users – and their capacity for creative agency – are positioned. I argue that the maintenance of balanced tensions between accessibility and openness is important to the ongoing prospects of social and cultural innovation in social media.

Media and information literacy : policy and strategy guidelines

In the evolving knowledge societies of today, some people are overloaded with information, others are starved for information. Everywhere, people are yearning to freely express themselves,to actively participate in governance processes and cultural exchanges. Universally, there is a deep thirst to understand the complex world around us. Media and Information Literacy (MIL) is a basis for enhancing access to information and knowledge, freedom of expression, and quality education. It describes skills, and attitudes that are needed to value the functions of media and other information providers, including those on the Internet, in societies and to find, evaluate and produce information and media content; in other words, it covers the competencies that are vital for people to be effectively engaged in all aspects of development.

Graphic death in the news media : present or absent?

The debate over the absence or presence of death in public discourse has dominated death studies for some time. While the argument that death had been removed from public discourse and only existed in the private realm dominated at first, in recent years scholars have come to accept that death has moved back into public discourse. An important aspect has been the role played by the mass media. However, there has been little empirical research as to what level of death is actually visible, for example in terms of photographs. To this end, this paper examines how two German and two Australian newspapers cover death in terms of graphic photographs. By examining the number and types of photographs published during a 2-month timeframe, as well as through in-depth interviews with journalists, this paper argues that visible death is still largely absent from public discourse. Importantly, there exist differences as to what level of graphic death is acceptable between individual newspapers, as well as countries, supporting the argument that the absence/presence of death dichotomy needs to be viewed in a much more complex light.

Media innovations, user innovations, societal innovations

As the Journal of Media Innovations comes into existence, this article reflects on the first and most obvious question: just what do we mean by “media innovations”? Drawing on the examples of a range of recent innovations in media technologies and practices, initiated by a variety of media audiences, users, professionals, and providers, it explores the interplay between the different drivers of innovation and the effects of such innovation on the complex frameworks of contemporary society and the media ecology which supports it. In doing so, this article makes a number of key observations: first, it notes that media innovation is an innovation in media practices at least as much as in media technologies, and that changes to the practices of media both reflect and promote societal changes as well – media innovations are never just media technology innovations. Second, it shows that the continuing mediatisation of society, and the shift towards a more widespread participation of ordinary users as active content creators and media innovators, make it all the more important to investigate in detail these interlinked, incremental, everyday processes of media and societal change – media innovations are almost always also user innovations. Finally, it suggests that a full understanding of these processes as they unfold across diverse interleaved media spaces and complex societal structures necessarily requires a holistic perspective on media innovations, which considers the contemporary media ecology as a crucial constitutive element of societal structures and seeks to trace the repercussions of innovations across both media and society – media innovations are inextricably interlinked with societal innovations (even if, at times, they may not be considered to be improvements to the status quo).

Tracking spatio temporal movement of human in terms of space utilization using media access control address data

Using Media-Access-Control (MAC) address for data collection and tracking is a capable and cost effective approach as the traditional ways such as surveys and video surveillance have numerous drawbacks and limitations. Positioning cell-phones by Global System for Mobile communication was considered an attack on people's privacy. MAC addresses just keep a unique log of a WiFi or Bluetooth enabled device for connecting to another device that has not potential privacy infringements. This paper presents the use of MAC address data collection approach for analysis of spatio-temporal dynamics of human in terms of shared space utilization. This paper firstly discuses the critical challenges and key benefits of MAC address data as a tracking technology for monitoring human movement. Here, proximity-based MAC address tracking is postulated as an effective methodology for analysing the complex spatio-temporal dynamics of human movements at shared zones such as lounge and office areas. A case study of university staff lounge area is described in detail and results indicates a significant added value of the methodology for human movement tracking. By analysis of MAC address data in the study area, clear statistics such as staff’s utilisation frequency, utilisation peak periods, and staff time spent is obtained. The analyses also reveal staff’s socialising profiles in terms of group and solo gathering. The paper is concluded with a discussion on why MAC address tracking offers significant advantages for tracking human behaviour in terms of shared space utilisation with respect to other and more prominent technologies, and outlines some of its remaining deficiencies.

Personal media and wireless cities : towards an urban spatial analysis

For the past decade, at least, varieties of small, hand held networked instruments have appeared on the global scene, selling in record numbers, and being utilized by all manner of persons from the old to the young; children, women, men, the wealthy and the poor and in all countries. Their presences bespeak a radical shift in telecommunications infrastructure and the future of communications. They are particularly visible in urban areas where mobile transmission network infrastructure (3G, 4G, cellular and Wi-Fi) is more established and substantial, options more plentiful, and density of populations more dramatic. These end user products—I phones, cell phones, Blackberries, DSi, DS, IPads, Zooms, and others – of the mobile communications industry are the latest, hottest globalized commodities. At the same time, wirelessness, or the state of being wireless, and therefore capable of taking along one's networks, communicating from unlikely spaces, and navigating with GPS, is a complex social, political and economic communications phenomenon of early 21st century life. This thesis examines the specter of being wireless in cities. It lends the entire idea an experimentally envisioned, historical and planned context wherein personalization of media tools is seen both as a design development of corporate, artistic, and military imagination, as well as a profound social phenomenon enabling new forms of sharing, belonging, and urban community. In doing that it asserts the parameters of a new mobile space which, aside from clear benefits to humankind by way of mobility, has reinscribed numerous categories including gender. Moreover, it posits the recognition of other, more nuanced theoretical spaces for complex readings of gender and gendered use, including some instantiation of the notion of 'network' itself as a cyborgian and gendered social form. Additionally, cities are studied as places where technology is not only quickly popularized, but is connected to larger political interests, such as the reading of data, tracking of information, and the new security culture. In so doing the work has been undertaken as an urban spatial analysis and experimental ethnography, utilizing architectural, feminist, techno-utopian, industrial and theoretical literatures as discursive underpinnings from whence understandings and interpretations of mobile space, the mobile office, networked mobility, and personal media have come, linking the space of cities to specific, pioneering urban public art projects in which voice, texting and MMS have been utilized in expressions of ubiquitous networks and urban history. Through numerous examples of techno art, the thesis discusses the 'wireless city' as an emerging cultural, socially constructed economic and spatial entity, both conceived and formed through historic processes of urbanization.