A New Receiver for a Digital Passband System with CPSK Modulation: The STTS-CPSK Receiver

671-677Telecommunications industry is expanding vastly with huge infrastructure requiring huge sums of money for investment1,2. Reliability of the system3,4, efficient utilization of resources1,2, and safety of the users and the environment are paramount towards providing high quality efficient telecom services at affordable prices1,2. This paper deals with an important scientific investigation for the development of the STTS-CPSK receiver for pass band applications5,6 . This is a new receiver being developed with the inspiration from the previously developed STTS-MF receiver for baseband applications. This is carried out considering transmission of p-q signals (p-q signals represent correlated digital signals) through AWGN channel. Performance-comparison studies of the conventional STS-CPSK receiver and the new STTS-CPSK receiver are carried out for a wide range of signal and system parameters 0.0 ≤ p,q ≤ 1.0 and-10 dB ≤ SNR ≤ 10 dB. Performance superiority of the STTS-CPSK receiver is established for 0.0 ≤ p,q ≤ 1.0, -2 dB ≤ SNR ≤ 10 dB, and illustrated. Thus, this work has important implications towards efficient utilization of bandwidth, and also in greening of communication technologies which is highly needed. The latter is because the performance-improvement, achieved in case of STTS-CPSK receiver, can be translated into an equivalent advantage of EMF-reduction appropriately

Medical applicant general practice experience and career aspirations: a questionnaire study

Background: Increasing access to general practice work experience placements for school students is a strategy for improving general practice recruitment, despite limited evidence and concerns surrounding equity of access to general practice experiences. Aims: To examine the association between undertaking general practice experience and the perceptions of general practice as an appealing future career among prospective medical applicants. To identify socioeconomic factors associated with obtaining general practice experience. Design & setting: Cross-sectional questionnaire study in the UK. Method: Participants were UK residents aged ≥16 years and seriously considering applying to study medicine in 2019/2020. They were invited to take part via the University Clinical Aptitude Test (UCAT). Questionnaire data were analysed using a linear regression of general practice appeal on general practice experience, adjusting for career motivations and demographics, and a logistic regression of general practice experience on measures of social capital and demographics. Results: Of 6391 responders, 4031 were in their last year of school. General practice experience predicted general practice appeal after adjusting for career motivation and demographics (b = 0.37, standard error [SE] = 0.06, P<0.00001). General practice experience was more common among students at private (odds ratio [OR] = 1.65, 95% confidence interval [CI] = 1.31 to 2.08, P<0.0001) or grammar schools (OR = 1.33, 95% CI = 1.02 to 1.72, P = 0.03) and in the highest socioeconomic group (OR = 1.62, 95% CI = 1.28 to 2.05, P<0.0001), and less likely among students of ‘other’ ethnicity (OR = 0.37, 95% CI = 0.20 to 0.67, P = 0.0011). Conclusion: Having general practice experience prior to medical school was associated with finding general practice appealing, which supports its utility in recruitment. Applicants from more deprived backgrounds were less likely to have had a general practice experience, possibly through lack of accessible opportunities

An approach to modelling open networks with unreliable servers and finite buffers.

Networks of queues are extensively used in modelling transaction processing systems, and the interactions among nodes in communication networks. Today, many practical queuing systems widely used in computing and communication have finite capacities. Often, in such systems, servers are prone to failures. In this paper, the performance modelling of a multi-node system, with heterogeneous nodes, each node serving external as well as routed internal arrivals of jobs is considered. An analytical model has been developed with certain approximations, and solved for performability measures. In an attempt to improve accuracy in performability evaluation, assumptions made have been minimised and a series of computations have been performed for open queuing networks with breakdowns, repairs, and finite queuing capacity. Results obtained using the analytical model are validated through simulation and presented

Analytical modelling and simulation of small scale, typical and highly available Beowulf clusters with breakdowns and repairs

Beowulf clusters are very popular because of the high computational power they can provide at reasonably low costs. However, the most pressing issues of today’s cluster solutions are the need for high availability and performance. Cluster systems are clearly prone to failures. Even if cover is provided with some probability c, there would be reconfiguration and/or rebooting delays to resume the operation following a failure. In this paper, the performability modelling of both typical and highly available Beowulf multiprocessor systems is presented. The models developed provide a large degree of flexibility to evaluate the performability of typical and highly available Beowulf cluster systems

Modelling open networks with breakdowns, repairs and finite buffers: using an IPP departure process model

Open queuing network systems are useful in the computer industry. In this paper, a multi-node open network, with heterogeneous nodes, each node serving external as well as routed internal arrivals of jobs is considered. The nodes are prone to failures and repairs, the buffers are of finite size. An approximate performability model is developed based on an IPP departure process. External Poisson arrivals and routed internal arrivals are modelled together using an MMPP model. Results have been validated via simulation

A New Receiver for a Passband System with CFSK Modulation: The STTS-CFSK Receiver

692-699A new receiver, named STTS-CFSK receiver, for passband with CFSK modulation, is developed. This new receiver uses correlations in the transmitted digital signals wisely, while assuming the correlation parameters p and q known at the receiver. The conventional receiver, the STS-CFSK receiver, does not take these correlations into consideration. Both the receivers are evaluated and compared, by extensive simulation based experimentation. Performance of the STTS-CFSK receiver is found to be superior to that of the STS-CFSK receiver, for SNR > 0 dB. Usefulness of this work for ‘Greening of Communication Technology’ is explaine