Cooperative communications in ultra-wideband wireless body area networks: Channel modeling and system diversity analysis

In this paper, we explore the application of cooperative communications in ultra-wideband (UWB) wireless body area networks (BANs), where a group of on-body devices may collaborate together to communicate with other groups of on-body equipment. Firstly, time-domain UWB channel measurements are presented to characterize the body-centric multipath channel and to facilitate the diversity analysis in a cooperative BAN (CoBAN). We focus on the system deployment scenario when the human subject is in the sitting posture. Important channel parameters such as the pathloss, power variation, power delay profile (PDP), and effective received power (ERP) crosscorrelation are investigated and statistically analyzed. Provided with the model preliminaries, a detailed analysis on the diversity level in a CoBAN is provided. Specifically, an intuitive measure is proposed to quantify the diversity gains in a single-hop cooperative network, which is defined as the number of independent multipaths that can be averaged over to detect symbols. As this measure provides the largest number of redundant copies of transmitted information through the body-centric channel, it can be used as a benchmark to access the performance bound of various diversity-based cooperative schemes in futuristic body sensor systems.

Socialising young literacy learners into a discourse of failure: Dominant discourses in literacy teaching and assessment and their impact on the progression of young literacy learners into employment

This paper argues that contemporary literacy programmes are a mismatch for the expectations of both the government and employers as well as the goals of learners. It submits that the dominant discourses in literacy provision have led to the emergence of a learning culture which not only fails the learners but is also incapable of meeting the aspirations of both the government and employers. To support this argument, the paper reports a small scale research project that analyses the perceptions of learners, teachers and employers who were involved in a work placement scheme for young literacy learners in a college of further education. Data for the study were collected through focus group and face to face interviews and analysed using the framework of discourse analysis provided by Gill (2000) with findings codified and analysed thematically. The study found that teachers were aware that their learners were not adequately prepared for the world of work because of the demands of the dominant discourses of quality and performance measurement which were most obviously manifested in their assessment, teaching methods and the attitudes of learners. It found that employers perceive young learners as inadequate in terms of the workplace expectations. Learners in the study revealed that their workplace culture and expectations were totally different from the culture to which they had been socialised in their studies. The study concludes that unless the dominance of these discourses is ameliorated, young literacy learners will continue to be socialised into a discourse of failure.

Effect of machine dependence on wall failure property measurements, Jenike versus an annular shear tester

Annular, ring or torsional shear testers are commonly used in bulk solids handling research for the purpose of powder characterisation or equipment design. This paper reports from a DEFRA sponsored project which aims to develop an industrial powder flow-ability tester, (based on the annular shear tester) that is economic to buy and quick and easy to use in trained but unskilled hands. This paper compares the wall failure loci measured with an annular shear cell with measurements obtained using the accepted standard wall friction tester, the Jenike shear cell. These wall failure loci have been measured for several bulk solids which range from fine cohesive powders to free-flowing granular materials, on a stainless steel 304 2B wall surface.