A novel soft decision QAM demodulator for DVB-T for multipath system

In 1997, the United Kingdom started the world's first commercial digital terrestrial television service. The system used was the European Digital Video Broadcast - Terrestrial (DVB-T) but due to technological constraints at the time, the system chosen was the 2K system - a system that uses 1705 carriers to convey the digital television services through a hostile terrestrial environment. Today, these constraints are no longer applicable but in order to maintain backwards compatibility to the older set top boxes, the 2K system is still used. The 2K system has the disadvantage of excluding the possibiliiy of employing a Single Frequency Network (SFN) - something that can help minimise the required bandwidth for television services. This paper will demonstrate a computationally inexpensive soft decision Quadrature Amplitude Modulation technique that can reject the multipaths. (1).

Design considerations for the multiband OFDM physical layer in consumer electronic products

The creation of Wireless Personal Area Networks (WPANs) offers the Consumer Electronics industry a mechanism to truly unwire consumer products, leading to portability and ease of installation as never seen before. WPAN's can offer data-rates exceeding those that are required to convey high quality broadcast video, thus users can easily connect to high quality video for multimedia presentations in education, libraries, advertising, or have a wireless connection at home. There have been many WPAN proposals, but this paper concentrates on ECMA-368 as this standard has the largest industrial and implementers' forum backing. This paper discusses the technology behind ECMA-368, the required numerical bandwidth, buffer memory requirements and implementation considerations while concentrating on supporting all the offered data-rates'.

Offering 802.11 MAC frame transport over multiband OFDM for consumer devices

A method to map all the variants of the IEEE 802.11 MAC frames into the Multiband OFDM based ECMA-368 Physical standard is proposed, without contravening the standard. The transportation of IEEE 802.11 MAC frames over ECMA-368 allows for the migration current of Wireless LAN applications towards a Wireless Personal Area Network (WPAN) solution. This system benefits the Consumer Electronics Market as the high data-rate WPAN is capable of transporting broadcast-quality video while the same system can also transport existing applications available today, maintaining existing effort, products and backward-compatibility(1).

An analysis on the performance of the forward and return interaction channels in DVB-RCS

The next generation consumer level interactive services require reliable and constant communication for both mobile and static users. The Digital Video Broadcasting ( DVB) group has exploited the rapidly increasing satellite technology for the provision of interactive services and launched a standard called Digital Video Broadcast through Return Channel Satellite (DYB-RCS). DVB-RCS relies on DVB-Satellite (DVB-S) for the provision of forward channel. The Digital Signal processing (DSP) implemented in the satellite channel adapter block of these standards use powerful channel coding and modulation techniques. The investigation is concentrated towards the Forward Error Correction (FEC) of the satellite channel adapter block, which will help in determining, how the technology copes with the varying channel conditions and user requirements(1).

Performance and conformance results of the deterministic DVB-T equalizer

One of the enablers for new consumer electronics based products to be accepted in to the market is the availability of inexpensive, flexible and multi-standard chipsets and services. DVB-T, the principal standard for terrestrial broadcast of digital video in Europe, has been extremely successful in leading to governments reconsidering their targets for analogue television broadcast switch-off. To enable one further small step in creating increasingly cost effective chipsets, the ODFM deterministic equalizer has been presented before with its application to DVB-T. This paper discusses the test set-up of a DVB-T compliant baseband simulation that includes the deterministic equalizer and DVB-T standard propagation channels. This is then followed by a presentation of the found inner and outer Bit Error Rate (BER) results using various modulation levels, coding rates and propagation channels in order to ascertain the actual performance of the deterministic equalizer(1).

Design issues toward a cost effective physical layer for multiband OFDM (ECMA-368) in consumer products

The creation of Wireless Personal Area Networks (WPANs) offers the Consumer Electronics industry a mechanism to truly unwire consumer products, leading to portability and ease of installation as never seen before. WPAN's can offer data-rates exceeding those that are required to convey high quality broadcast video, thus users can easily connect to high quality video for multimedia presentations in education, libraries, advertising, or have a wireless connection at home. There have been many WPAN proposals, but this paper concentrates on ECMA-368 as this standard has the largest industrial and implementers' forum backing. With the aim to effective consumer electronic define and create cost equipment this paper discusses the technology behind ECMA-368 physical layer, the design freedom availabilities, the required processing, buffer memory requirements and implementation considerations while concentrating on supporting all the offered data-rates(1).

Associations between dairy consumption and body weight: a review of the evidence and underlying mechanisms

As the incidence of obesity is reaching 'epidemic' proportions, there is currently widespread interest in the impact of dietary components on body-weight and food intake regulation. The majority of data available from both epidemiological and intervention studies provide evidence of a negative but modest association between milk and dairy product consumption and BMI and other measures of adiposity, with indications that higher intakes result in increased weight loss and lean tissue maintenance during energy restriction. The purported physiological and molecular mechanisms underlying the impact of dairy constituents on adiposity are incompletely understood but may include effects on lipolysis, lipogeneis and fatty acid absorption. Furthermore, accumulating evidence indicates an impact of dairy constituents, in particular whey protein derivatives, on appetite regulation and food intake. The present review summarises available data and provides an insight into the likely contribution of dairy foods to strategies aimed at appetite regulation, weight loss or the prevention of weight gain.

Testing Turing's five minutes, parallel-paired imitation game

Purpose – The purpose of this paper is to consider Turing's two tests for machine intelligence: the parallel-paired, three-participants game presented in his 1950 paper, and the “jury-service” one-to-one measure described two years later in a radio broadcast. Both versions were instantiated in practical Turing tests during the 18th Loebner Prize for artificial intelligence hosted at the University of Reading, UK, in October 2008. This involved jury-service tests in the preliminary phase and parallel-paired in the final phase. Design/methodology/approach – Almost 100 test results from the final have been evaluated and this paper reports some intriguing nuances which arose as a result of the unique contest. Findings – In the 2008 competition, Turing's 30 per cent pass rate is not achieved by any machine in the parallel-paired tests but Turing's modified prediction: “at least in a hundred years time” is remembered. Originality/value – The paper presents actual responses from “modern Elizas” to human interrogators during contest dialogues that show considerable improvement in artificial conversational entities (ACE). Unlike their ancestor – Weizenbaum's natural language understanding system – ACE are now able to recall, share information and disclose personal interests.

Genome sequences of the human body louse and its primary endosymbiont provide insights into the permanent parasitic lifestyle

As an obligatory parasite of humans, the body louse (Pediculus humanus humanus) is an important vector for human diseases, including epidemic typhus, relapsing fever, and trench fever. Here, we present genome sequences of the body louse and its primary bacterial endosymbiont Candidatus Riesia pediculicola. The body louse has the smallest known insect genome, spanning 108 Mb. Despite its status as an obligate parasite, it retains a remarkably complete basal insect repertoire of 10,773 protein-coding genes and 57 microRNAs. Representing hemimetabolous insects, the genome of the body louse thus provides a reference for studies of holometabolous insects. Compared with other insect genomes, the body louse genome contains significantly fewer genes associated with environmental sensing and response, including odorant and gustatory receptors and detoxifying enzymes. The unique architecture of the 18 minicircular mitochondrial chromosomes of the body louse may be linked to the loss of the gene encoding the mitochondrial single-stranded DNA binding protein. The genome of the obligatory louse endosymbiont Candidatus Riesia pediculicola encodes less than 600 genes on a short, linear chromosome and a circular plasmid. The plasmid harbors a unique arrangement of genes required for the synthesis of pantothenate, an essential vitamin deficient in the louse diet. The human body louse, its primary endosymbiont, and the bacterial pathogens that it vectors all possess genomes reduced in size compared with their free-living close relatives. Thus, the body louse genome project offers unique information and tools to use in advancing understanding of coevolution among vectors, symbionts, and pathogens.

Television and the popular: viewing from the British perspective

The academic discipline of television studies has been constituted by the claim that television is worth studying because it is popular. Yet this claim has also entailed a need to defend the subject against the triviality that is associated with the television medium because of its very popularity. This article analyses the many attempts in the later twentieth and twenty-first centuries to constitute critical discourses about television as a popular medium. It focuses on how the theoretical currents of Television Studies emerged and changed in the UK, where a disciplinary identity for the subject was founded by borrowing from related disciplines, yet argued for the specificity of the medium as an object of criticism. Eschewing technological determinism, moral pathologization and sterile debates about television's supposed effects, UK writers such as Raymond Williams addressed television as an aspect of culture. Television theory in Britain has been part of, and also separate from, the disciplinary fields of media theory, literary theory and film theory. It has focused its attention on institutions, audio-visual texts, genres, authors and viewers according to the ways that research problems and theoretical inadequacies have emerged over time. But a consistent feature has been the problem of moving from a descriptive discourse to an analytical and evaluative one, and from studies of specific texts, moments and locations of television to larger theories. By discussing some historically significant critical work about television, the article considers how academic work has constructed relationships between the different kinds of objects of study. The article argues that a fundamental tension between descriptive and politically activist discourses has confused academic writing about ›the popular‹. Television study in Britain arose not to supply graduate professionals to the television industry, nor to perfect the instrumental techniques of allied sectors such as advertising and marketing, but to analyse and critique the medium's aesthetic forms and to evaluate its role in culture. Since television cannot be made by ›the people‹, the empowerment that discourses of television theory and analysis aimed for was focused on disseminating the tools for critique. Recent developments in factual entertainment television (in Britain and elsewhere) have greatly increased the visibility of ›the people‹ in programmes, notably in docusoaps, game shows and other participative formats. This has led to renewed debates about whether such ›popular‹ programmes appropriately represent ›the people‹ and how factual entertainment that is often despised relates to genres hitherto considered to be of high quality, such as scripted drama and socially-engaged documentary television. A further aspect of this problem of evaluation is how television globalisation has been addressed, and the example that the issue has crystallised around most is the reality TV contest Big Brother. Television theory has been largely based on studying the texts, institutions and audiences of television in the Anglophone world, and thus in specific geographical contexts. The transnational contexts of popular television have been addressed as spaces of contestation, for example between Americanisation and national or regional identities. Commentators have been ambivalent about whether the discipline's role is to celebrate or critique television, and whether to do so within a national, regional or global context. In the discourses of the television industry, ›popular television‹ is a quantitative and comparative measure, and because of the overlap between the programming with the largest audiences and the scheduling of established programme types at the times of day when the largest audiences are available, it has a strong relationship with genre. The measurement of audiences and the design of schedules are carried out in predominantly national contexts, but the article refers to programmes like Big Brother that have been broadcast transnationally, and programmes that have been extensively exported, to consider in what ways they too might be called popular. Strands of work in television studies have at different times attempted to diagnose what is at stake in the most popular programme types, such as reality TV, situation comedy and drama series. This has centred on questions of how aesthetic quality might be discriminated in television programmes, and how quality relates to popularity. The interaction of the designations ›popular‹ and ›quality‹ is exemplified in the ways that critical discourse has addressed US drama series that have been widely exported around the world, and the article shows how the two critical terms are both distinct and interrelated. In this context and in the article as a whole, the aim is not to arrive at a definitive meaning for ›the popular‹ inasmuch as it designates programmes or indeed the medium of television itself. Instead the aim is to show how, in historically and geographically contingent ways, these terms and ideas have been dynamically adopted and contested in order to address a multiple and changing object of analysis.

Communicability across evolving networks

Many natural and technological applications generate time ordered sequences of networks, defined over a fixed set of nodes; for example time-stamped information about ‘who phoned who’ or ‘who came into contact with who’ arise naturally in studies of communication and the spread of disease. Concepts and algorithms for static networks do not immediately carry through to this dynamic setting. For example, suppose A and B interact in the morning, and then B and C interact in the afternoon. Information, or disease, may then pass from A to C, but not vice versa. This subtlety is lost if we simply summarize using the daily aggregate network given by the chain A-B-C. However, using a natural definition of a walk on an evolving network, we show that classic centrality measures from the static setting can be extended in a computationally convenient manner. In particular, communicability indices can be computed to summarize the ability of each node to broadcast and receive information. The computations involve basic operations in linear algebra, and the asymmetry caused by time’s arrow is captured naturally through the non-mutativity of matrix-matrix multiplication. Illustrative examples are given for both synthetic and real-world communication data sets. We also discuss the use of the new centrality measures for real-time monitoring and prediction.

Social networks, migration, and care in Tanzania

This paper explores the impacts of the HIV/AIDS epidemic on children and families in northern Tanzania using the concept of social resilience.1 The study is based on the findings of childfocused research with street children and children and families from HIV/AIDS-affected households. The paper illustrates the coping strategies that children and young people, and parents and caregivers adopt at the household level. In particular, it examines how the burden of care affects different generations of women and highlights their resilience, together with the importance of social networks and the fluidity of movement between rural and urban areas. The research suggests that migrating to urban areas to seek a living in the informal sector represents a survival strategy adopted by some children and young people orphaned by AIDS when their families and communities are unable or unwilling to support them. The paper concludes by exploring parents’, caregivers’, children’s, and young people’s views on the forms of social support that would promote their resilience and thereby help to mitigate the impacts of the epidemic at the household level.

Poverty, HIV, and barriers to education: street children's experiences in Tanzania

This article discusses the links between poverty, HIV/AIDS, and barriers to education, based on the first-hand experiences of ‘street children’ in northern Tanzania. Within the context of national levels of poverty, ‘cost-sharing’ in health and education sectors, and the AIDS epidemic, poor families in Tanzania are under considerable pressure, and increasing numbers of girls and boys are consequently seeking a living independently on the streets of towns and cities. My research with street children shows that some children orphaned by AIDS are subject to rejection and exploitation by the extended family after the death of their parent(s). They are exposed to considerable risks of abuse, sexual violence and HIV within the street environment. Here, I discuss the links between poverty, HIV and barriers to education, which compound young people’s vulnerability, and offer some policy recommendations in response to the young people’s experiences.

Nostalgia, music and the television past revisited in American dreams

The 1960s-set NBC family drama American Dreams presents not just the recent American past but its musical television as well. This paper examines how the show’s recreation of and interaction with the music show American Bandstand ties together the divergent experiences of a turbulent decade. American Dreams’ reshooting and appropriation of original broadcast footage is intricately interwoven with dramatic action allowing for new layers of commentary and meaning to be read across the music and image relationship. Through intercutting and juxtaposition, its use of music performance goes beyond the regressive recycling of images of nostalgia, as critiqued by Jameson and other theorists of postmodernity, to engage political and social debates through a complex web of reference, reproduction and commentary, presenting a politicised reading of the 1960s that problematises these charges of nostalgia texts as apolitical and ‘historicist’.

Symmetric Push-Sum Protocol for decentralised aggregation

Gossip (or Epidemic) protocols have emerged as a communication and computation paradigm for large-scale networked systems. These protocols are based on randomised communication, which provides probabilistic guarantees on convergence speed and accuracy. They also provide robustness, scalability, computational and communication efficiency and high stability under disruption. This work presents a novel Gossip protocol named Symmetric Push-Sum Protocol for the computation of global aggregates (e.g., average) in decentralised and asynchronous systems. The proposed approach combines the simplicity of the push-based approach and the efficiency of the push-pull schemes. The push-pull schemes cannot be directly employed in asynchronous systems as they require synchronous paired communication operations to guarantee their accuracy. Although push schemes guarantee accuracy even with asynchronous communication, they suffer from a slower and unstable convergence. Symmetric Push- Sum Protocol does not require synchronous communication and achieves a convergence speed similar to the push-pull schemes, while keeping the accuracy stability of the push scheme. In the experimental analysis, we focus on computing the global average as an important class of node aggregation problems. The results have confirmed that the proposed method inherits the advantages of both other schemes and outperforms well-known state of the art protocols for decentralized Gossip-based aggregation.