A flexible receiver-driven cache replacement scheme for continuous media objects in best-effort networks

In this paper, we investigate the potential of caching to improve quality of reception (QoR) in the context of continuous media applications over best-effort networks. Specifically, we investigate the influence of parameters such as loss rate, jitter, delay and area in determining a proxy's cache contents. We propose the use of a flexible cost function in caching algorithms and develop a framework for benchmarking continuous media caching algorithms. The cost function incorporates parameters in which, an administrator and or a client can tune to influence a proxy's cache. Traditional caching systems typically base decisions around static schemes that do not take into account the interest of their receiver pool. Based on the flexible cost function, an improvised Greedy Dual (GD) algorithm called GD-multi has been developed for layered multiresolution multimedia streams. The effectiveness of the proposed scheme is evaluated by simulation-based performance studies. Performance of several caching schemes are evaluated and compared with those of the proposed scheme. Our empirical results indicate GD-multi performs well despite employing a generalized caching policy.

A cache-based mobility-aware scheme for real-time continuous media delivery in wireless networks

Providing real-time or continuous media (CM) application services in wireless networks poses a significant challenge, as it requires timely delivery of data in a best-effort network. In this paper, we propose a cache-based scheme for mobility-aware, CM applications. The proposed scheme exploits a previously proposed caching strategy to complement Mobile-IP by placing services closer to migrated mobile nodes. The central idea of this work is based on the migration of sessions in order to facilitate uninterrupted delivery of CM in mobile environments. The performance of the proposed scheme is investigated by simulation studies. In particular, the effect of the proposed scheme on several QoS parameters under varying conditions of mobility and CM data is measured.

A generalised cost-aware caching scheme for caching continuous media objects in best-effort network environments

In this paper, we investigate the potential of caching to improve QoS in the context of continuous media applications over wired best-effort networks. We propose the use of a flexible caching scheme, called GD-Multi in caching continuous media (CM) objects. An important novel feature of our scheme is the provision of user or system administrator inputs in determining the cost function. Based on the proposed flexible cost function, Multi, an improvised Greedy Dual (GD) replacement algorithm called GD-multi (GDM) has been developed for layered multi-resolution multimedia streams. The proposed Multi function takes receiver feedback into account. We investigate the influence of parameters such as loss rate, jitter, delay and area in determining a proxy’s cache contents so as to enhance QoS perceived by clients. Simulation studies show improvement in QoS perceived at the clients in accordance to supplied optimisation metrics. From an implementation perspective, signalling requirements for carrying QoS feedback are minimal and fully compatible with existing RTSP-based Internet applications.

A cooperative cache architecture in support of caching multimedia objects in MANETs

This paper presents a cooperative caching architecture suitable for continuous media (CM) proxy caching in MANET environments. The proposed scheme introduces an application manager component, which is interposed between traditional Internet CM applications and the network layer. The application manager transparently performs data location and service migration of active CM streaming sessions so as to exploit nearby data sources based on the dynamic topology of a MANET. We propose two data location schemes - Cache-State - a link-state based scheme and Reactive - an on-demand scheme. Since service migration can occur frequently, the application manager uses soft-state signaling techniques to communicate between remote application managers by translating hard-state application signaling, such as Real Time Streaming Protocol (RTSP) into soft-state messages. The proposed schemes are evaluated through simulation studies using the NS simulator. Simulation studies show that both Cache-State and Reactive schemes demonstrate significant QoS improvements and reduced bandwidth consumption.

A microfluidic system for testing the responses of head and neck squamous cell carcinoma tissue biopsies to treatment with chemotherapy drugs

Tumors are heterogeneous masses of cells characterized pathologically by their size and spread. Their chaotic biology makes treatment of malignancies hard to generalize. We present a robust and reproducible glass microfluidic system, for the maintenance and “interrogation” of head and neck squamous cell carcinoma (HNSCC) tumor biopsies, which enables continuous media perfusion and waste removal, recreating in vivo laminar flow and diffusion-driven conditions. Primary HNSCC or metastatic lymph samples were subsequently treated with 5-fluorouracil and cisplatin, alone and in combination, and were monitored for viability and apoptotic biomarker release ‘off-chip’ over 7 days. The concentration of lactate dehydrogenase was initially high but rapidly dropped to minimally detectable levels in all tumor samples; conversely, effluent concentration of WST-1 (cell proliferation) increased over 7 days: both factors demonstrating cell viability. Addition of cell lysis reagent resulted in increased cell death and reduction in cell proliferation. An apoptotic biomarker, cytochrome c, was analyzed and all the treated samples showed higher levels than the control, with the combination therapy showing the greatest effect. Hematoxylin- and Eosin-stained sections from the biopsy, before and after maintenance, demonstrated the preservation of tissue architecture. This device offers a novel method of studying the tumor environment, and offers a pre-clinical model for creating personalized treatment regimens.

Investigation of educator adoption of knowledge media

Human development has occurred against a timeline that has seen the creation of and diffusion of one innovation after another. These innovations range from language to complex computing and information technologies. The latter are assisting with the distribution of information, and extend to the distribution of the human species beyond the planet Earth. From early times, information has been published and mostly for a fee to the publisher. The absorption and use of information has had a high priority in most societies from early times, and has become institutionalised in universities and institutes of technical learning. For most in Western societies, education is now a matter of ‘lifelong learning’. Today, we see higher education institutions, worldwide, adapting their organisational structures and operating procedures and forming strategic alliances with communications content providers and carriers as well as with information technology companies. Modern educational institutes seek productivity and efficiency. Many also seek to differentiate themselves from competitors. Technological convergence is often seen by management to be a saviour in many educational organisations. It is hoped that lower capital and recurrent costs can be achieved, and that competitors in an increasingly globalised industry can be held at bay by strategic use of knowledge media (Eisenstadt, 1995) commonly associated with distance education in the campus setting. Knowledge media set up costs, intellectual property costs and training costs for staff and students are often so high as to make their use not viable for Australian institutes of higher education. Against this backdrop, one might expect greater educator and student use of publisher produced textbooks and digital enhancements to the textbook, particularly those involved in distance education. A major issue is whether or not the timing of instructor adoption of converging information technology and communications technologies aligns with the wishes of both higher education management and government, and with those who seek commercial gain from the diffusion and adoption of such technologies. Also at issue is whether or not it is possible to explain variance in stated intentions to recommend adoption of new learning technologies in higher education and implementation. Will there occur educator recommendation for adoption of individual knowledge media such as World Wide Web access to study materials by students? And what will be the form of this tool and others used in higher education? This thesis reports on more recent changes in the technological environment and seeks to contribute to an understanding of the factors that lead to a willingness, or unwillingness, on the part of higher education instructors, as influencers and content providers, to utilise these technologies. As such, it is a diffusion study which seeks to fill a gap in the literature. Diffusion studies typically focus on predicting adoption based on characteristics of the potential adopter. Few studies examine the relationship between characteristics of the innovation and adoption. Nearly all diffusion studies involve what is termed discontinuous innovation (Robertson, 1971). That is, the innovation involves adoptees in a major departure from previous practice. This study seeks to examine the relationship between previous experience of related technologies and adoption or rejection of dynamically continuous innovation. Continuous and dynamically continuous innovations are the most numerous in the real world, yet they are numerically the least scrutinised by way of academic research. Moreover, the three-year longitudinal study of educators in Australian and New Zealand meets important criteria laid down by researchers Tornatzky and Klein (1982) and Rogers (1995), that are often not met by similar studies. In particular the study examines diffusion as it is unfolding, rather than selectively examining a single innovation and after the fact, thus avoiding a possible pro-innovation bias. The study examines the situation for both ‘all educators’ and ‘marketing / management educators’ alone in seeking to meet the following aim: Establish if intended adopters of specific knowledge media have had more experience of other computer-based technologies than have those not intending to adopt said knowledge media. The analytical phase entails use of factor analysis and discriminant analysis to conclude that it is possible to discriminate adopters of selected knowledge media based on previous use of related technologies. The study does not find any generalised factor that enables such discrimination among educators. Thus the study supports the literature in part, but fails to find generalised factors that enable unambiguous prediction of knowledge media adoption or otherwise among each grouping of educators examined. The implications are that even in the case of related products and services (continuous or dynamically continuous innovation), there is not statistical certainty that prior usage of related products or technologies is related to intentions to use knowledge media in the future. In this regard, the present study might be said to confirm the view that Rogers and Shoemaker's (1971) conceptualisation of perceived innovation characteristics may only apply to discontinuous innovations (Stratton, Lumpkin & Vitell, 1997). The implications for stakeholders such as higher education management is that when seeking to appoint new educators or existing staff to knowledge media project teams, there is some support for the notion that those who already use World Wide Web based technologies are likely to take these technologies into teaching situations. The same claim cannot be made for computer software use in general, nor Internet use in general.

One tweet does not a revolution make : technological determinism, media and social change

This paper discusses the problematic influence of technological determinism in popular news media coverage and analysis of the Arab Spring events of 2010-11.

The purpose is to develop insights into how and why elements of a ‘soft’ technological determinism inflect both journalistic practice and news discourse in relation to the Arab Spring. In particular it discusses how the ‘bias of convenience’ and a journalistic obsession with the ‘continuous present’ connect with this determinist inflection to create a potential distortion in the journalists’ ‘first rough draft’ of history in relation to significant and complex events such as social revolution.

What is the role of tobacco control advertising intensity and duration in reducing adolescent smoking prevalence? Findings from 16 years of tobacco control mass media advertising in Australia

ABSTRACT
Objective: To examine how the intensity and duration of tobacco control advertising relate to adolescent smoking prevalence.
Methods: Australian students (aged 12–17 years) participating in a national survey conducted triennially between 1993 and 2008 (sample size range 12 314–16 611). The outcome measure was students’ smoking in the previous 4 weeks collected through anonymous, self-completed surveys. For each student, monthly targeted rating points (TRPs, a measure of television advertising exposure) for tobacco control advertising was calculated for the 3 and 12 months prior to surveying. For each time period, cumulative TRPs exposure and exposure to three intensity levels (≥100 TRPs/month; ≥400 TRPs/month; ≥800 TRPs/month) over increasing durations (eg, 1 month, 2 months, etc) were calculated. Logistic regression examined associations between TRPs and adolescent smoking after controlling for demographic and policy variables.
Results: Past 3-month cumulative TRPs were found to have an inverse relationship with smoking prevalence. Low TRPs exposure in the past 12 months was positively associated with adolescent smoking prevalence. However, smoking prevalence reduced with cumulative exposure levels above 5800 cumulative TRPs. Additionally, exposure to ≥400 TRPs/month and ≥800 TRPs/month were associated with reduced likelihood of smoking, although the duration needed for this effect differed for the two intensity levels. When intensity was ≥400 TRPs/month, the odds of smoking only reduced with continuous exposure. When intensity was ≥800 TRPs/month, exposure at levels less than monthly was associated with reductions in smoking prevalence.
Conclusions: Both antismoking advertising intensity and duration are important for ensuring reductions in adolescent smoking prevalence.

Social media as an information system : improving the technological agility

There is an increased focus on research involving social media. This research however has failed to catch up with the pace of the technology development and may prove disadvantageous for both practice and theory. The longitudinal study presented in the paper was conducted over a 3-year period involving Australian banks and popular social media technologies. The paper empirically tests the Honeycomb model as a tool that enhances the technological agility of social media. The paper fills a key research gap and provides dynamism to social media strategy formation, continuous improvement of strategy development in support of greater business agility.