Adaptive GPS duty cycling and radio ranging for energy-efficient localization

This paper addresses the tradeoff between energy consumption and localization performance in a mobile sensor network application. The focus is on augmenting GPS location with more energy-efficient location sensors to bound position estimate uncertainty in order to prolong node lifetime. We use empirical GPS and radio contact data from a largescale animal tracking deployment to model node mobility, GPS and radio performance. These models are used to explore duty cycling strategies for maintaining position uncertainty within specified bounds. We then explore the benefits of using short-range radio contact logging alongside GPS as an energy-inexpensive means of lowering uncertainty while the GPS is off, and we propose a versatile contact logging strategy that relies on RSSI ranging and GPS lock back-offs for reducing the node energy consumption relative to GPS duty cycling. Results show that our strategy can cut the node energy consumption by half while meeting application specific positioning criteria.

Public service broadcasting, creative industries and innovation infrastructure : the case of ABC's Pool

The proliferation of media services enabled by digital technologies poses a serious challenge to public service broadcasting rationales based on media scarcity. Looking to the past and future, we articulate an important role that the Australian Broadcasting Corporation (ABC) might play in the digital age. We argue that historically the ABC has acted beyond its institutional broadcasting remit to facilitate cultural development and, drawing on the example of Pool (an online community of creative practitioners established and maintained by the ABC), point to a key role it might play in fostering network innovation in what are now conceptualised as the creative industries.

Digital broadcasting : a double edge sword in protecting children from disturbing news content

New technologies have the potential to both expose children to and protect them from television news footage likely to disturb or frighten. The advent of cheap, portable and widely available digital technology has vastly increased the possibility of violent news events being captured and potentially broadcast. This material has the potential to be particularly disturbing and harmful to young children. But on the flipside, available digital technology could be used to build in protection for young viewers especially when it comes to preserving scheduled television programming and guarding against violent content being broadcast during live crosses from known trouble spots. Based on interviews with news directors, parents and a review of published material two recommendations are put forward: 1. Digital television technology should be employed to prevent news events "overtaking" scheduled children's programming and to protect safe harbours placed in the classifications zones to protect children. 2. Broadcasters should regain control of the images that go to air during "live" feeds from obviously volatile situations by building in short delays in G classification zones.

Current affairs in British public service broadcasting : challenges and opportunities

This chapter looks at the challenges and opportunities of current affairs in British public service broadcasting

The younger audience : children and broadcasting in New Zealand

The role and influence of media in the lives of children are ongoing sources of public, political and academic debates. These debates move back and forth along a care-control continuum (Cohen, 1997), and reflect a commitment both to educate children and to regulate their media experiences. Rapid advancements in computer technologies have vastly expanded the range of media experiences available to children. The development of Internet information and the rapid expansion of channels as a result of digital television have created increasingly accessible and diverse sources of media for children. These media are instantaneous and, in some circumstances, constantly available. As a result, a substantial body of international research has emerged that examines the influence of media consumption on children. How much time do children spend interacting with media? What sorts of media do they access? Are media harmful or beneficial to children? If so, in which contexts? Do media influence children�s personal development? And what role should governments, broadcasters and independent producers play in the regulation of the media? These questions remain central to contemporary debates about children and the media.

Beyond broadcasting: customer service, community and information experience in the Twittersphere

What opportunities does a channel like Twitter offer to libraries, beyond the realm of marketing? We would like to highlight three roles for Twitter in the academic library environment: Twitter as a service delivery and service recovery channel; Twitter as a community builder; Twitter as a site for information experience.

Spectrum sensing, detection and optimisation in cognitive radio for non-stationary primary user signals

Cognitive radio is an emerging technology proposing the concept of dynamic spec- trum access as a solution to the looming problem of spectrum scarcity caused by the growth in wireless communication systems. Under the proposed concept, non- licensed, secondary users (SU) can access spectrum owned by licensed, primary users (PU) so long as interference to PU are kept minimal. Spectrum sensing is a crucial task in cognitive radio whereby the SU senses the spectrum to detect the presence or absence of any PU signal. Conventional spectrum sensing assumes the PU signal as ‘stationary’ and remains in the same activity state during the sensing cycle, while an emerging trend models PU as ‘non-stationary’ and undergoes state changes. Existing studies have focused on non-stationary PU during the transmission period, however very little research considered the impact on spectrum sensing when the PU is non-stationary during the sensing period. The concept of PU duty cycle is developed as a tool to analyse the performance of spectrum sensing detectors when detecting non-stationary PU signals. New detectors are also proposed to optimise detection with respect to duty cycle ex- hibited by the PU. This research consists of two major investigations. The first stage investigates the impact of duty cycle on the performance of existing detec- tors and the extent of the problem in existing studies. The second stage develops new detection models and frameworks to ensure the integrity of spectrum sensing when detecting non-stationary PU signals. The first investigation demonstrates that conventional signal model formulated for stationary PU does not accurately reflect the behaviour of a non-stationary PU. Therefore the performance calculated and assumed to be achievable by the conventional detector does not reflect actual performance achieved. Through analysing the statistical properties of duty cycle, performance degradation is proved to be a problem that cannot be easily neglected in existing sensing studies when PU is modelled as non-stationary. The second investigation presents detectors that are aware of the duty cycle ex- hibited by a non-stationary PU. A two stage detection model is proposed to improve the detection performance and robustness to changes in duty cycle. This detector is most suitable for applications that require long sensing periods. A second detector, the duty cycle based energy detector is formulated by integrat- ing the distribution of duty cycle into the test statistic of the energy detector and suitable for short sensing periods. The decision threshold is optimised with respect to the traffic model of the PU, hence the proposed detector can calculate average detection performance that reflect realistic results. A detection framework for the application of spectrum sensing optimisation is proposed to provide clear guidance on the constraints on sensing and detection model. Following this framework will ensure the signal model accurately reflects practical behaviour while the detection model implemented is also suitable for the desired detection assumption. Based on this framework, a spectrum sensing optimisation algorithm is further developed to maximise the sensing efficiency for non-stationary PU. New optimisation constraints are derived to account for any PU state changes within the sensing cycle while implementing the proposed duty cycle based detector.

The new normativity : the innovation imperative

At a quite fundamental level, the very way in which Public Service Broadcasting (PSB) may envisage its future usually captured in the semantic shift from PSB to Public Service Media (PSM) is at stake when considering the recent history of public value discourse and the public value test. The core Reithian PSB idea assumed that public value would be created through the application of core principles of universality of availability and appeal, provision for minorities, education of the public, distance from vested interests, quality programming standards, program maker independence, and fostering of national culture and the public sphere. On the other hand, the philosophical import of the public value test is that potentially any excursion into the provision of new media services needs to be justified ex ante. In this era of New Public Management, greater transparency and accountability, and the proposition that resources for public value deliverables be contestable and not sequestered in public sector institutions, what might be the new Archimedean point around which a contemporised normativity for PSM be built? This paper will argue for the innovation imperative as an organising principle for contemporary PSM. This may appear counterintuitive, as it is precisely PSB’s predilection for innovating in new media services (in online, mobile, and social media) that has produced the constraining apparatus of the ex ante/public value/Drei-Stufen-Test in Europe, based on principles of competitive neutrality and transparency in the application of public funds for defined and limited public benefit. However, I argue that a commitment to innovation can define as complementary to, rather than as competitive ‘crowding out’, the new products and services that PSM can, and should, be delivering into a post-scarcity, superabundant all-media marketplace. The evidence presented in this paper for this argument is derived mostly from analysis of PSM in the Australian media ecology. While no PSB outside Europe is subject to a formal public value test, the crowding out arguments are certainly run in Australia, particularly by powerful commercial interests for whom free news is a threat to monetising quality news journalism. Take right wing opinion leader, herself a former ABC Board member, Judith Sloan: ‘… the recent expansive nature of the ABC – all those television stations, radio stations and online offerings – is actually squeezing activity that would otherwise be undertaken by the private sector. From partly correcting market failure, the ABC is now causing it. We are now dealing with a case of unfair competition and wasted taxpayer funds’ (The Drum, 1 August http://www.abc.net.au/unleashed/2818220.html). But I argue that the crowding out argument is difficult to sustain in Australia because of the PSB’s non-dominant position and the fact that much of innovation generated by the two PSBs, the ABC and the SBS, has not been imitated by or competed for by the commercials. The paper will bring cases forward, such as SBS’ Go Back to Where you Came From (2011) as an example of product innovation, and a case study of process and organisational innovation which also has resulted in specific product and service innovation – the ABC’s Innovation Unit. In summary, at least some of the old Reithian dicta, along with spectrum scarcity and market failure arguments, have faded or are fading. Contemporary PSM need to justify their role in the system, and to society, in terms of innovation.

Energy-efficient localization : GPS duty cycling with radio ranging

GPS is a commonly used and convenient technology for determining absolute position in outdoor environments, but its high power consumption leads to rapid battery depletion in mobile devices. An obvious solution is to duty cycle the GPS module, which prolongs the device lifetime at the cost of increased position uncertainty while the GPS is off. This article addresses the trade-off between energy consumption and localization performance in a mobile sensor network application. The focus is on augmenting GPS location with more energy-efficient location sensors to bound position estimate uncertainty while GPS is off. Empirical GPS and radio contact data from a large-scale animal tracking deployment is used to model node mobility, radio performance, and GPS. Because GPS takes a considerable, and variable, time after powering up before it delivers a good position measurement, we model the GPS behaviour through empirical measurements of two GPS modules. These models are then used to explore duty cycling strategies for maintaining position uncertainty within specified bounds. We then explore the benefits of using short-range radio contact logging alongside GPS as an energy-inexpensive means of lowering uncertainty while the GPS is off, and we propose strategies that use RSSI ranging and GPS back-offs to further reduce energy consumption. Results show that our combined strategies can cut node energy consumption by one third while still meeting application-specific positioning criteria.

Life of SYN : a story of the digital generation

SYN (Student Youth Network) is a media organisation run by people between the ages of 12 and 26. In this ‘coming of age story’, Ellie Rennie follows the SYNners as they build Australia’s most unusual media empire against enormous odds. Over the course of the book, social networking becomes the most popular use of the internet and traditional media institutions are forced to acknowledge the rise of amateur content. In response, SYN rethinks its approach to the online environment, kills its print publication, deals with the introduction of digital broadcasting and teaches schoolteachers about a new kind of literacy. In just two years dozens of careers are launched, the SYN radio audience doubles and they get told off for swearing. Life of SYN takes on the big issues of the media through the story of a small media organisation. This humorous and insightful book describes a media environment in flux, where audiences and producers express their freedom in unruly and contradictory ways. Life of SYN gives structure to the new media world without curtailing its inventiveness and possibility. Life of SYN combines story with media theory, encompassing: digital literacy and media participation; the future of community media; youth media and media industries.

Pregnancy loss and mental health

Between 8 and 20 percent of depression in young men and women aged 18-23 is associated with pregnancy loss, according to a recent analysis of the 30 year Mater Hospital longitudinal study of mothers and children. Dr Kaeleen Dingle from the University of Queensland explains the study and discusses the implications for both men and women.