Body-shadowing effects in indoor MIMO-OFDM channel capacity

We investigate Multiple-Input and Multiple-Output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) systems behavior in indoor populated environments that have line-of-site (LoS) between transmitter and receiver arrays. The in-house built MIMO-OFDM packet transmission demonstrator, equipped with four transmitters and four receivers, has been utilized to perform channel measurements at 5.2 GHz. Measurements have been performed using 0 to 3 pedestrians with different antenna arrays (2 £ 2, 3 £ 3 and 4 £ 4). The maximum average capacity for the 2x2 deterministic Fixed SNR scenario is 8.5 dB compared to the 4x4 deterministic scenario that has a maximum average capacity of 16.2 dB, thus an increment of 8 dB in average capacity has been measured when the array size increases from 2x2 to 4x4. In addition a regular variation has been observed for Random scenarios compared to the deterministic scenarios. An incremental trend in average channel capacity for both deterministic and random pedestrian movements has been observed with increasing number of pedestrian and antennas. In deterministic scenarios, the variations in average channel capacity are more noticeable than for the random scenarios due to a more prolonged and controlled body-shadowing effect. Moreover due to the frequent Los blocking and fixed transmission power a slight decrement have been observed in the spread between the maximum and minimum capacity with random fixed Tx power scenario.

Utilizing robustness of positive buck-boost converter against input voltage and load current disturbances

A Positive Buck- Boost (PBB) converter is a known DC-DC converter that can operate in step up and step down modes. Unlike Buck, Boost, and Inverting Buck Boost converters, the inductor current of a PBB can be controlled independently of its voltage conversion ratio. In other words, the inductor of PBB can be utilised as an energy storage unit in addition to its main function of energy transfer. In this paper, the capability of PBB to store energy has been utilised to achieve robustness against input voltage fluctuations and output current changes. The control strategy has been developed to keep accuracy, affordability, and simplicity acceptable. To improve the efficiency of the system a Smart Load Controller (SLC) has been suggested. Applying SLC extra current storage occurs when there is sudden loads change otherwise little extra current is stored.

Third space in cyberspace : Indigenous youth, new technologies and literacies

This chapter analyses the affordances and constraints of an online literacy program designed for Indigenous Australian youth through a partnership between the Indigenous community, university staff and local schools. The after-school program sought to build on the cultural resources and experiences of the young people through a dialogic process of planning, negotiating, implementing, reflecting, and renegotiating the program with participants and a range of stakeholders. In the majority of cases, students presented themselves as part of pervasive global popular cultures, often hot-linking their webpages to pop icons and local sports stars. Elders regarded their competency as a potential cultural tool and community resource.

Towards Humane Technologies: Biotechnologies, New Media and Ethics

What are the ethical and political implications when the very foundations of life —things of awe and spiritual significance — are translated into products accessible to few people? This book critically analyses this historic recontextualisation. Through mediation — when meaning moves ‘from one text to another, from one discourse to another’ — biotechnology is transformed into analysable data and into public discourses. The unique book links biotechnology with media and citizenship. As with any ‘commodity’, biological products have been commodified. Because enormous speculative investment rests on this, risk will be understated and benefit will be overstated. Benefits will be unfairly distributed. Already, the bioprospecting of Southern megadiverse nations, legally sanctioned by U.S. property rights conventions, has led to wealth and health benefits in the North. Crucial to this development are biotechnological discourses that shift meanings from a “language of life” into technocratic discourses, infused with neo-liberal economic assumptions that promise progress and benefits for all. Crucial in this is the mass media’s representation of biotechnology for an audience with poor scientific literacy. Yet, even apparently benign biotechnology spawned by the Human Genome Project such as prenatal screening has eugenic possibilities, and genetic codes for illness are eagerly sought by insurance companies seeking to exclude certain people. These issues raise important questions about a citizenship that is founded on moral responsibility for the wellbeing of society now and into the future. After all, biotechnology is very much concerned with the essence of life itself. This book provides a space for alternative and dissident voices beyond the hype that surrounds biotechnology.

Using Media Technologies in English

English has long been the subject where print text has reigned supreme. Increasingly in our networked and electronically connected world, however, we can be using digital technologies to create and respond to texts studied in English classrooms. The current approach to English includes the concept of ‘multiliteracies,’ which suggests that print texts alone are necessary but not sufficient’ (E.Q, 2000) and that literacy includes the flexible and sustainable mastery of a repertoire of practices. This also includes the decoding and deployment of media technologies (E.Q, 2000). This has become more possible in Australia as secondary students have increasing access to computers and online platforms at home and at school. With the advent of web 2.0., with its interactive platforms and free media making software, teachers and students can use this software to access information and emerging online literature in English covering a range of text types and new forms for authentic audiences and contexts. This chapter is concerned with responding to literary and mediated texts through the use of technologies. If we remain open to trying out new textual forms and see our digital ‘native students’ (Prensky, 2007) as our best resource, we can move beyond technophobia, become digital travellers’ ourselves and embrace new digital forms in our classrooms.

Trajectories of broadband : the coming, going and return of broadband

As the paper’s subtitle suggests broadband has had a remarkably checkered trajectory in Australia. It was synonymous with the early 1990s information superhighway and seemed to presage a moment in which “content is [to be] king”. It disappeared almost entirely as a public priority in the mid to late 1990s as intrastructure and content were disconnected in services frameworks focused on information and communication technologies. And it came back in the 2000s as a critical infrastructure for innovation and the knowledge economy. But this time content was not king but rather an intermediate input at the service of innovating industries and processes. Broadband was a critical infrastructure for the digitally-based creative industries. Today the quality of the broadband infrastructure in Australia—itself an outcome of these different policy frameworks—is identified as “fraudband” holding back business, creativity and consumer uptake. In this paper I use the checkered trajectory of broadband on Australian political and policy horizons as a stepping off point to reflect on the ideas governing these changing governmental and public settings. This history enables me to explore how content and infrastructure are simultaneously connected and disconnected in our thinking. And, finally, I want to make some remarks about the way communication, particularly media communication, has been marginally positioned after being, initially so apparently central.

Managing ubiquitous eco cities : the role of urban telecommunication infrastructure networks and convergence technologies

A successful urban management system for a Ubiquitous Eco City requires an integrated approach. This integration includes bringing together economic, socio-cultural and urban development with a well orchestrated, transparent and open decision making mechanism and necessary infrastructure and technologies. Rapidly developing information and telecommunication technologies and their platforms in the late 20th Century improves urban management and enhances the quality of life and place. Telecommunication technologies provide an important base for monitoring and managing activities over wired, wireless or fibre-optic networks. Particularly technology convergence creates new ways in which the information and telecommunication technologies are used. The 21st Century is an era where information has converged, in which people are able to access a variety of services, including internet and location based services, through multi-functional devices such as mobile phones and provides opportunities in the management of Ubiquitous Eco Cities. This paper discusses the recent developments in telecommunication networks and trends in convergence technologies and their implications on the management of Ubiquitous Eco Cities and how this technological shift is likely to be beneficial in improving the quality of life and place. The paper also introduces recent approaches on urban management systems, such as intelligent urban management systems, that are suitable for Ubiquitous Eco Cities.

Intelligent prognostics of machinery health utilising suspended condition monitoring data

The ability to forecast machinery failure is vital to reducing maintenance costs, operation downtime and safety hazards. Recent advances in condition monitoring technologies have given rise to a number of prognostic models for forecasting machinery health based on condition data. Although these models have aided the advancement of the discipline, they have made only a limited contribution to developing an effective machinery health prognostic system. The literature review indicates that there is not yet a prognostic model that directly models and fully utilises suspended condition histories (which are very common in practice since organisations rarely allow their assets to run to failure); that effectively integrates population characteristics into prognostics for longer-range prediction in a probabilistic sense; which deduces the non-linear relationship between measured condition data and actual asset health; and which involves minimal assumptions and requirements. This work presents a novel approach to addressing the above-mentioned challenges. The proposed model consists of a feed-forward neural network, the training targets of which are asset survival probabilities estimated using a variation of the Kaplan-Meier estimator and a degradation-based failure probability density estimator. The adapted Kaplan-Meier estimator is able to model the actual survival status of individual failed units and estimate the survival probability of individual suspended units. The degradation-based failure probability density estimator, on the other hand, extracts population characteristics and computes conditional reliability from available condition histories instead of from reliability data. The estimated survival probability and the relevant condition histories are respectively presented as “training target” and “training input” to the neural network. The trained network is capable of estimating the future survival curve of a unit when a series of condition indices are inputted. Although the concept proposed may be applied to the prognosis of various machine components, rolling element bearings were chosen as the research object because rolling element bearing failure is one of the foremost causes of machinery breakdowns. Computer simulated and industry case study data were used to compare the prognostic performance of the proposed model and four control models, namely: two feed-forward neural networks with the same training function and structure as the proposed model, but neglected suspended histories; a time series prediction recurrent neural network; and a traditional Weibull distribution model. The results support the assertion that the proposed model performs better than the other four models and that it produces adaptive prediction outputs with useful representation of survival probabilities. This work presents a compelling concept for non-parametric data-driven prognosis, and for utilising available asset condition information more fully and accurately. It demonstrates that machinery health can indeed be forecasted. The proposed prognostic technique, together with ongoing advances in sensors and data-fusion techniques, and increasingly comprehensive databases of asset condition data, holds the promise for increased asset availability, maintenance cost effectiveness, operational safety and – ultimately – organisation competitiveness.

L'étendue internationale des nouvelles firmes de hautes technologies: le rôle du capital humain et de l'intention stratégique des fondateurs

De récentes recherches ont mis l’accent sur l’importance pour les nouvelles entreprises internationales de l’existence de ressources et de compétences spécifiques. La présente recherche, qui s’inscrit dans ce courant, montre en particulier l’importance du capital humain acquis par les entrepreneurs sur base de leur expérience internationale passée. Mais nous montrons en même temps que ces organisations sont soutenues par une intention délibérée d’internationalisation dès l’origine. Notre recherche empirique est basée sur l’analyse d’un échantillon de 466 nouvelles entreprises de hautes technologies anglaises et allemandes. Nous montrons que ce capital humain est un actif qui facilite la pénétration rapide des marchés étrangers, et plus encore quand l’entreprise nouvelle est accompagnée d’une intention stratégique délibérée d’internationalisation. Des conclusions similaires peuvent être étendues au niveau des ressources que l’entrepreneur consacre à la start-up : plus ces ressources sont importantes, plus le processus d’internationalisation tend à se faire à grande échelle ; et là aussi, l’influence de ces ressources est augmenté par l’intention stratégique d’internationalisation. Dans le cadre des études empiriques sur les born-globals (entreprises qui démarrent sur un marché globalisé), cette recherche fournit une des premières études empiriques reliant l’influence des conditions initiales de création aux probabilités de croissance internationale rapide.

Synopolies: The use of cryptographic technologies to impede competition in multiple jurisdictions

Many jurisdictions have developed mature infrastructures, both administratively and legislatively, to promote competition. Substantial funds have been expended to monitor activities that are anticompetitive and many jurisdictions also have adopted a form of "Cartel Leniency Program", first developed by the US Federal Trade Commission, to assist in cartel detection. Further, some jurisdictions are now criminalizing cartel behaviour so that cartel participants can be held criminally liable with substantial custodial penalties imposed. Notwithstanding these multijurisdictional approaches, a new form of possibly anticompetitive behaviour is looming. Synergistic monopolies („synopolies‟) involve not competitors within a horizontal market but complimentors within separate vertical markets. Where two complimentary corporations are monopolists in their own market they can, through various technologies, assist each other to expand their respective monopolies thus creating a barrier to new entrants and/or blocking existing participants from further participation in that market. The nature of the technologies involved means that it is easy for this potentially anti-competitive activity to enter and affect the global marketplace. Competition regulators need to be aware of this potential for abuse and ensure that their respective competition frameworks appropriately address this activity. This paper discusses how new technologies can be used to create a synopoly.

A general approach to control a positive buck-boost converter to achieve robustness against input voltage fluctuations and load changes

A Positive Buck-Boost converter is a known DC-DC converter which may be controlled to act as Buck or Boost converter with same polarity of the input voltage. This converter has four switching states which include all the switching states of the above mentioned DC-DC converters. In addition there is one switching state which provides a degree of freedom for the positive Buck-Boost converter in comparison to the Buck, Boost, and inverting Buck-Boost converters. In other words the Positive Buck-Boost Converter shows a higher level of flexibility for its inductor current control compared to the other DC-DC converters. In this paper this extra degree of freedom is utilised to increase the robustness against input voltage fluctuations and load changes. To address this capacity of the positive Buck-Boost converter, two different control strategies are proposed which control the inductor current and output voltage against any fluctuations in input voltage and load changes. Mathematical analysis for dynamic and steady state conditions are presented in this paper and simulation results verify the proposed method.

Multi-output buck-boost converter with enhanced dynamic response to load and input voltage changes

This paper presents a new multi-output DC/DC converter topology that has step-up and step-down conversion capabilities. In this topology, several output voltages can be generated which can be used in different applications such as multilevel converters with diode-clamped topology or power supplies with several voltage levels. Steady state and dynamic equations of the proposed multi-output converter have been developed, that can be used for steady state and transient analysis. Two control techniques have been proposed for this topology based on constant and dynamic hysteresis band height control to address different applications. Simulations have been performed for different operating modes and load conditions to verify the proposed topology and its control technique. Additionally, a laboratory prototype is designed and implemented to verify the simulation results.